The annual average, maximum, and minimum temperature data from Chaoyang, Haidian, and Fengtai (Beijing urban area) from 1975 to 2012 are studied. The results show: (1) Temperature in Beijing in recent 40 years increased significantly, and the warming rates of annual mean, maximum and minimum air temperature are 0445, 033, and 05 ℃ per 10 years, respectively; the warming in Beijing was most significant in the 1990’s and 2000’s. (2) The M K method is used to test temperature jumps in Beijing, and the results indicate that there were jumps in average, maximum, and minimum temperature with time in 1992, 1992, and 1991, respectively. (3) After the mutation, the average minimum temperature rose most noticeably with the rising amplitude up to 11 ℃, then the average temperature and maximun temperature, with the rising amplitudes being 10 ℃ and 08 ℃. (4) After the mutation, the number of high temperature days increased, while the number of cold days reduced, but precipitation decreased; precipitation and temperature change with anti phase distribution.