That Manjusri Belief reached its summit in Tang Dynasty and had direct relation with the state power. First, the religion policy in the early period of Tang Dyansty Laid the foundation for the development of Buddhism. Second, it was promoted by the royalty's canonizing Wu Tai Mountaion. Third, Wu Zetian impeled it throughout the whole country. Finally, it meeted the political need in the middle of Tang by being endowed by the Mi School with the function of protecting kings and countries, and then it obtained the entire support from Dai Zong Dynasty.