According to the development of grottoes' shape, carving content and style, the Buddhist art of Yungang Grottoes can be divided into three stages: early, middle and late.

Early grottoes

That is, 16 ~ 20 caves, also known as Tan Yao Cave 5. According to Shu Wei Shi Lao Zhi (volume 1 14), "At the beginning of Taiping, my mentor died. Yao Tan replaced it with Samoan system. At the beginning, Yao Tan was ordered to go to Beijing from Zhongshan in the second year after the political reform. He was found on the road, wearing an obsidian coat in front of the imperial horse. At that time, people thought that Ma knew good people, so the emperor gave it to his teacher as a gift. Bai Di, Yao Tan, in Saiwu County, the capital, chiseled stone walls, opened five caves, carved Buddha statues, each 70 feet high and 60 feet for the second time, which is the highest in the world. " The five caves mentioned in this paper, namely the famous monk Yao Tan at that time, chose Yuzhou Mountain in Zhong Ling and dug the magnificent Tan Yao Cave, which opened the prelude to the excavation of Yungang Grottoes. Caves 16~20 are the five largest caves in Tan Yao and the symbol of the emperor. The plane is horseshoe-shaped, with a dome and thousands of buddhas carved on the outer wall. The main statue is Buddha III, with a tall figure, round face, high nose, deep eyes and straight shoulders, showing a strong, vigorous and simple sculpture style. Its carving skills inherited and developed the excellent tradition of Han Dynasty, absorbed and integrated the essence of ancient Indian Gandhara and Datura art, and created a unique artistic style.

Mid-term grottoes

It is the heyday of Yungang grottoes sculpture, mainly including 1 and 2 caves, 5 and 6 caves, 7 and 8 caves, 9 caves and 10 caves,1caves, 12 caves, 13 caves and 3 unfinished caves. This period (47 1-494) was the period of filial piety before the Northern Wei Dynasty moved its capital to Luo, and it was the most stable and prosperous period in the Northern Wei Dynasty. Yungang Grottoes have concentrated outstanding talents from all over the country and carved more prosperous and exquisite statues of Yungang Grottoes with national strength as the guarantee. Before Emperor Xiaowen moved to the capital, all the large grottoes operated by the royal family had been completed, which lasted for more than 40 years. In the middle period, most of the caves are square or rectangular, and some caves are carved with central towers or front and rear rooms. The wall layout is divided into two layers, left and right. There are at most flat chess caissons in the cave. The diversity of sculpture themes highlights the status of Sakyamuni and Maitreya. The two buddhas, Sakyamuni and Duobao, are popular and sit side by side, resulting in the ranks of protector, prostitute and provider, the Buddha's own behavior, origin, karma and the story of Vimalakīrti. Buddha statues are round and moderate in appearance, especially in the form of praise belts, which are popular, and many new themes and statues have emerged, mainly in the image of dharma protection and various decorations. The middle grottoes were also a period of active reform and innovation, which set off the process of China-ization of Buddhist grottoes. These factors are combined to form the so-called grandeur and style. The main feature is the rapid development of sinicization, and the art of China Grottoes started and completed in this period, which is the middle period of Yungang Grottoes. Its complicated content and exquisite carving art are very different from those of early grottoes, and its carving style is neat and gorgeous, with obvious Chinese characteristics from cave shape to carving content and style.

Late grottoes

After the Northern Wei Dynasty moved its capital to Luoyang (494), although the large-scale excavation of Yungang Grottoes stopped, the wind of carving caves and statues spread among the middle and lower classes. Pro-expensive, middle and lower officials and Yi believers made full use of Pingcheng's old skills and dug a large number of small and medium-sized caves in Yungang. The carving and construction of these small caves and shrines continued until the fifth year of Emperor Zheng Guang of Xiaoming (524). Pingcheng, as the capital of the north, was still an important Buddhist place in the Northern Wei Dynasty. At this time, there are few caves, and small and medium-sized caves are covered with cliffs from east to west. Mainly distributed in the west of No.20 cave, including No.4 cave, 14 cave, 15 cave and 1 1 cave. There are about 200 small and medium-sized caves. Most caves appear in the form of single holes and are no longer grouped. The themes of the statues are mostly Sakyamuni or Maitreya Buddha above and Sakyamuni below. Buddhas and Bodhisattvas have thin bodies, long necks and narrow shoulders. This kind of statue is a fresh and elegant artistic image of "showing bones and clearing images" after the "Sinicization" reform in the late Northern Wei Dynasty, and it has become a remarkable feature of Buddhist statues in the late Northern Wei Dynasty. This feature and style is also reflected in the Northern Wei Cave in Longmen Grottoes, which has a far-reaching impact on the development of China Cave Temple art.