Base on the surface observations of forty years(1960-2000),the variational characteristics of annual average temperature, maximum and minimum temperature in Harbin are analyzed. The results show that the whole area of Harbin has become notably warmer,but their warm extent is different,the observation stations close to city are evidently warmer than the suburbs,especially after the 1980's. There is also an evident difference in four seasons,the warm trend is evident in winter than that in summer. After 1980's,the cold duration evidently decreases,but the duration of "warm night" and hot evidently increases.