Buha River is the most important recharging source for Qinghai Lake. Analysis of the evolution of climate characteristics in Buha River basin has important significance to the ecological safety of Qinghai Lake. Based on the long series of temperature and precipitation data at Tianjun,Gangcha and Chaka stations,the climate characteristics in the river basin were analyzed. The results showed that the annual mean temperature continues to rise significantly at all the three stations. At Tianjun the highest station, the annual mean temperature has increased the most. Among the four seasons, the temperature increases the most in winter. Mann-Kendall trend analysis method and cumulative anomalies were used to analyze the temperature change o-ver the time. The temperature rise had a 10-year fluctuation period from 1986 to 1997,and then went through a significantly abrupt change in 1997. This coincides with the variation trend of temperature and precipitation on Qinghai-Tibet Plateau over the years. The annual precipitation also has increased,but not so significantly as the annual mean temperature. The increase is more significant at the higher station. Among the four seasons, the annual precipitation increases the most in summer. According to the temperature and the available precipitation, the basin is going through a continuous warm and wet period since the 1980's. It was relatively warm and dry in the 1990's,and then became warm and wet again in the first decade of this century.