According to the investigation and cleaning up in recent years and the excavation of Japanese during the Anti Japanese War, we gradually know that the great project in Yungang in Liao Dynasty is in line with the repeated renovations recorded in the inscriptions in the 18th year of Chongxi reign (1049), the 6th year of Qingning reign (1060), the 5th year of Xianyong reign (1069), the 5th year of shouchang reign (1099) and the 10th year of Tianqing reign of emperor Tianzuo (1120). At that time, the project started from Guanyintang and foziwan in the east of Yungang and ended at Jiaoshan Temple 30 Li west of Yungang. The contents of the project include: 1. The construction of the temple. 1. The construction of Guanyin hall and foziwan. Volume 15 of Qianlong Datong Fu Zhi: "Guanyin hall, foziwan, fifteen miles west of Fu Cheng, was built in 1037. In the third year of Xuande (1428) of Ming Dynasty, it was rebuilt in the 35th year of Wanli (1607) In 1649, Jiang Xiangbian was burned, and in 1651, governor Tong Yangliang rebuilt. It was built in the sixth year of the reign of Zhiyun Chongxi, according to the Ming people's inscriptions in Guanyin hall. Now there is still a statue of Guanyin carved in Liao Dynasty in Guanyin hall, and there are a lot of gouwen bricks in Guanyin hall and its vicinity. All these deeds can confirm the records of Fu Zhi. On the stone cliff in the west of Guanyintang, there is a double hook "Buddha" with a diameter of more than Zhang, which is also a relic of Liao Dynasty. 2. Construction in front of Yungang Grottoes the location of the ten temples of the Liao Dynasty has been largely confirmed by recent discoveries: (a) in 1933, when the Yungang villa was built, a stone foundation of the Liao Dynasty was found on the west side of the front of cave 5; (b) when the Yungang villa was built, a stone foundation of the Liao Dynasty was found on the west side of the front of cave 5 During the Anti Japanese War, the Japanese dug out Liao Dynasty square tiles, gouwen tiles, animal face tiles, Jialing Pinjia tiles, Zhiwen board tiles and ceramic tiles under the ground in front of cave 8, cave 9, cave 11, cave 12, cave 13 and tanyao cave 5; and dug out Liao Dynasty animal face tiles, Zhiwen board tiles, ceramic tiles and residual iron wares in the dragon temple between cave 5 and Cave 4; (c) In 1953, the Yungang historical site maintenance office also found Liao Dynasty bricks and tiles on the ground outside the cave to the west of cave 16. One of the most important things was the discovery of a section of brick masonry short wall on the destroyed stone wall to the east of cave 20. The brick of the short wall was the same as the Liao Dynasty gouwen brick on the top of cave 20. In this way, these two brick ruins can connect the beam hole on the backlight of Sakyamuni statue in cave 20 On the one hand, it can be estimated that these holes were chiseled during the installation of wooden buildings in the Liao Dynasty; on the other hand, it seems that the collapse of the top of cave 20 was before the restoration of the Liao people. As a result of the above findings, we can infer that the Liao dynasty built huge wooden buildings in front of these caves (some of which may have inherited the old foundation of the Northern Wei Dynasty), and these huge wooden buildings were connected with the caves. 3. Construction in front of the Luban kiln in 1952, a large number of Liao Dynasty bricks and tiles were found in front of the Luban kiln (two caves excavated in the Northern Wei Dynasty), which shows that Liao people also built temples here. 4. Construction of Jiaoshan temple in 1950, Liao Dynasty gouwen bricks were found on the south slope of Jiaoshan and on the east side of Jiaoshan temple. Liao people not only built them here, but also made clay sculptures on the eroded Buddha statues in the caves of Northern Wei Dynasty. The statues of Sakyamuni in the East cave on the second floor of the temple still have the stone green color commonly seen in the Five Dynasties and Northern Song Dynasty. 2、 The restoration of statues in Yungang Grottoes in the Liao Dynasty is also very large. On the lower part of the south wall of cave 13, the characters of "Khitan" and "Yelu" are engraved on the niche, and the sentence "repair 1876 statues" is also included. The last year of "Wu Wu" is estimated to be 1078 A.D., that is, the fourth year of Taikang of Liao daozong (according to this, it was destroyed during the Anti Japanese War). According to the observation of the existing relics, we know that some of the Yungang statues were decorated in the Liao Dynasty. Some of them were clay sculptures on the outside of the denuded statues, and some were made up of blank stone walls. The former had a large number of statues, such as the sitting statue of Sakyamuni on the east wall of cave 37 and the last two statues of seven Buddhas on the west wall of cave 11. The latter is less, such as the left and right flanks in the south of the central pillar of cave 11. 3、 The decorations of the statues are from the statues to the west of cave 14, which are mostly like the stone green paintings on the Liao sculptures of Jiaoshan temple. This kind of stone green, in the stone green backlight behind the statue of Sakyamuni sitting on the east wall of cave 37, has been directly proved by the times. This is because the backlight flower script is the popular compendium script and long type rhombic script in Liao Dynasty. This kind of flower inscription can also be seen in the backlight of Liao statue Sakya in the Bojia sect collection of xiahuayan temple in Datong City, the Liao Dynasty color painting on the Liang Fang of the seven Buddha Hall of Fengguo temple in Yixian County, Liaoning Province, and the color painting of Shiyang horse behind the East Mausoleum of liaoqing mausoleum in Linxi, Inner Mongolia. 4、 The destruction of Yungang at the end of Liao Dynasty. In 1122, Emperor Tianzuo fled from the central capital to the West and entered the Tiande army through Yungang On the fourteenth day of the first month, (Aguda) rode hard for 300 Li a day and a night until he attacked all of them. From the first day to the middle of the day, he was trapped. In the beginning, it was said that Tianzuo was in the city, and it was broken, but it was known that Tianzuo had heard that he had come, and that he had fled in the middle of the night Nuzhen lost Tianzuo and sent his pursuers out of the Pingdi pine forest (notes in the famous mountains and rivers in the Tibetan world in Volume 16 of the first collection of the general principles of Wujing: "Pingdi pine forest, 40 Li to huaizhou in the East and 700 Li to Youzhou in the southwest"), and also went to yuanyangpo in the west, which was suitable for meeting Tianzuo. Tianzuo was in great embarrassment. He rushed from Yunzhong mansion to Tiande army from Grottoes temple. ". In the second year of Jin Dading (1162), sengsheng studied the book of rebuilding Bojia religion in Tibet, which says: "in the last year of Baoda, when the Dynasty opened orthodoxy, Tianbing was a drum, the capital was in four depressions, and the pavilions and pavilions were in ruins" (this monument is now in the Bojia religion collection of lower Huayan Temple). In 1176, Zhu Bian's stele on the rebuilding of the main hall of dapun temple in Xijing also said: "since ancient times, the name of Dadu PUEN temple in Dajin was dalanruo. After the Liao Dynasty, it was repeatedly burned by beacon fire. The pavilions and halls were piled up with rubble. The only remaining pillars of the temple the day before yesterday were not three or four" (this stele is now in the three gates of Shanhua Temple). This is the case inside the city, and it can be seen outside the city that the grotto temple where Tianzuo fled to the west is no exception. Therefore, the inscription says: "first, the Liao Dynasty was destroyed, the thieves swarmed up, the temple was burned and looted, and the Lingyan pillars were completely destroyed.". The ten temples recorded in the inscriptions were more or less destroyed, and Lingyan suffered the worst.