The seasonal changing characteristics of OLR field over Qinghai-Xizang Plateau increases unceasingly from Janurary to May, and increases rapidly in March to May.It increases constantly in the Northern Plateau from May to August. Because of influences of the Indian monsoon in the Southern Plateau, the convection activity becomes stronger and a low-value zone of the OLR field appears. The low-value zone of May is in the southeast, and then spreads toward the northwest from the southeast crossing the Himalayas, and reaches the proximity of the northern latitude 31 in July. The low-value zone begins to withdraw to the southeast from the northwest in August, and to the southern side of the Himalayas in September. Because of the influences of the northwest currents at the outset of October, the OLR field value begins to drop from the northwest Plateau quickly and the southeast slowly. The characteristics of the annual variation curve are: it is a single-front type in the northern Plateau for the OLR with the highest value in August. It is a double-front type in the southern Plateau with the highest value in May and October respectively. It reaches the lowest-value in July.