There are an internal reason as well as an external cause that Buddhism could enter China and underwent the process of sinification.
Internal reason：Before the advent of Buddhism there was a prefusion of thoughts in China but this was of a very low order.Moreover the Chinese society and the government were in a chaotic condition. Precisely，the ruling clique in North China was without any culture and they wanted to pacify the society and the mind of the people through Buddhism.
External reason：As Han dynasty ran the administration of western region，the Buddhism could enter the interior part of China. In the Tang period the China administration became firmly established in this region; this facilitated the communication between India and China and the flow of dharma from one country to another.The scholars travelled uninterruptedly in search of dharma.
Because of these causes there was a mutual interaction between the culture and thoughts of these two countries. In China the theology of Taoism of Lao-tzu mixed with the prajnca philosophy and religious thoughts of Buddhism. Moreover the Confucianism of Duke Chou mixed with the spirit of compassion and universal love of Buddhism.
Later the Buddhist in China, such as six schools, seven sects, Tien-tai，Hwa-yeng Zen schools, etc.，all of them developed in the same way，but the style and form of them were different. So this article mainly discusses the procedure by which Buddhism became Chinese in style and form.
