College of Soil and Water Conservation and Desertification Combating, Ministry of Education, Beijing Forestry University, Beijing 100083, China

Hydrogen(H)and Oxygen(O)stable isotope data of precipitation water in the north China area,which were collected at Baotou,Tianjin,Shijiazhuang and Taiyuan by IAEA/WMO/GNIP,were compiled to analyze their temporal and spatial variations and to trace their controlling factors.The results indicate that,the values of ��¹⁸O in north China precipitation are high in the half year of summer and low in the half year of winter,showing the significant monsoon climate precipitation characteristics of presenting precipitation amount effect during the half year of summer while presenting temperature effect during the half year of winter.The observed slopes and the intercepts of meteoric water lines in this study are smaller than those of averaged meteoric water lines for overall China or the world indicates that isotope fractionations in north China precipitation does not follow the Raleigh fractionation;the values of deuterium are high in the half year of winter and low in the half year of summer,this seasonal characteristics implies different evaporation conditions at their vapor sources.