Based on the monthly air temperature from 26 representative stations in Qinghai from 1961 to 2002, the standard weighted average air temperature sequence was given, and the characteristics of air temperature variation in recent 42 years in Qinghai was analyzed. The results show that air temperature in Qinghai has been increasing with a rate of 0.25 ~C per ten years. The annual averaged air temperature is the lowest in the 1960s, began to increase in the 1970s, and has been increasing significantly since the 1990s, with the highest ten-year averaged air temperature in the decade. The air temperature in Qinghai has evident seasonal and regional variation, and the variation tendencyies of maximum and minimum temperature are generally non-symmetry. The variation tendency of air temperature in Qinghai is consistent with that across China. The increasing rates of an- nual, autumn, and winter air temperature are much greater in Qinghai than those in other parts of China. The phase of air temperature variation is five to six years ahead in Qinghai of that in the whole China. This conclusion is in agreament with the viewpoint that the Qinghi-Tibet plateau is probably one of most sensitive areas to the climate change in China.