Abstract: In this paper the trends of temperature and precipitation in North China and Northeast China and their relationshop are analysed using observed data in the past 100 years in Beijing,Tianjin,Shenyang and Haerbin stations. The result indicats that in the past 100 years annual mean temperature and monthly mean temperature in January in winter have a increase trend. And the magnitade of increase is greater in Northeast China than that of in creast in North China,the magnitade of the monthly mean temperature in Jan in winter is greater than that of the annual mean temperature. The monthly mean temperature in July in summer is a decrease trend in some regions. There is a inverse correlation between monthly mean temperature and precipitation,especially for May,June,July.