Abstract: Based on experiments in different longitudes of the Tibetan Plateau, it is found that the Tibetan Plateau makes a heat pulley function on its surrounding areas in late spring and summer. The function always enhances southerlies and brings heavy rainfall and more latent heating over tropical land to southeast of the Tibet, prevail northerlies, less rainfall and more sensible heating over tropical land to southwest of the Tibet. Therefore, the onset of Asian summer monsoon often takes place on the eastern shore of sea lies to the south of the Tibetan Plateau. These show that the Tibetan Plateau anchor the onset site of Asian summer monsoon. Results also show that the existence of Tibetan Plateau modulates the Asian monsoon, and make the Asian summer rainfall to redistribute.