Hasi Mountain is located in the arid and semi-arid areas of the northwestern China. This mountain plays a very important ecological role in the local environment. Based on the spring flow and the stable isotopes of hydrogen and oxygen of the 9 sampling springs in the mountain area, we analyzed the sources and influencing factors of the spring flow as well as the characteristics of hydrogen and oxygen stable isotopes and its implications. The results show that the springs belong to bedrock fissure water. The flows show no obvious seasonal changes,which indicate that the flow may be affected by the aeration zone, water hold capacity of soil, catchment area and altitude.The spring hydrogen and oxygen stable isotopes present a linear relationship (δD = 5.7439δ18 O -10.6535), without seasonal variations.This suggestes that spring is supplied mainly by the precipitation, and affected by the strong evaporation. There is a significantly linear relationship between the altitude of the spring and δ18 O. Similarly,δD values show a linear relationship with thealtitude,while the correlation is not statistically significant. The results show that the hydrological processes in the Hasi Mountain eco-hydrology of forest in the semi-arid region is very complicated.