Rainfall is a crucial factor of hydrologic cycle, especially in arid region. The hydrogen and oxygen isotopic data of meteoric water in Urumqi, Yinchuan, Zhangye, Lanzhou, Pingliang, Xi’an and Lhasa were collected in this study to analyze the H and O isotopiccharacteristics, hydrological cycle and to establish the H and O isotopic standard for the Northwest China. In this paper, the δ18 O of summer half year display higher values than winter half year in W, Y, Z and L because of the temperature effect. Due to the complicated water vapor sources, the δ18 O values of meteoric water in Xi’an, which is located in the Guanzhong Basin, are controlled by temperature effect and rainfall effect in summer and winter half year respectively. The meteoric water in Pingliang has much more depleted O isotopic compositions in May to September than meteoric water in other areas with the same altitude, such as Pingliang. This abnormal O isotopic characteristics in Pingliang is related to the relatively weak urban heat island effect. In the Northwest China, the δD and δ18 O values of meteoric water are varying in the range of global meteoric water. The lower slope and intercept of regional meteoric water lines in investigated places, except Pingliang and Lhasa, than the Global Meteoric Water Line suggest the precipitation process of these places undergo strong evaporation and may mix with condensation waters from vapor of meteoric water in some local areas. The higher deuterium surplus in winter half year than in summer half year may indicate that the vapor sources or conditions of evaporation are different in winter and summer half year.