Abstract: Zhaosu-Tekes basin,located in the Southern Tianshan Mountains,is a wedge Cenozoic intermontane fault depression basin expanding from SWW to NEE,and a key area of agriculture and animal husbandry in the south of Ili Basin. With the increasing exploration and utility of water resources,this area is suffering seriously from water shortage and quality deterioration. Research on the relationship between surface water and groundwater is quite vital for ensuring a sustainable utilization of water resources. In this paper,a total of 29 groundwater samples,19 surface water samples and 6 spring water samples in August 2014 were collected,and major ions and stable isotopes(δ¹⁸O,δD) were analyzed;by using the Piper diagram,Gibbs diagram,ion ratio coefficient and Chloro-Alkaline index,the paper further analyzed the characteristics of the water chemical composition and its formation process,and analyzed the source composition of the water by the composition relationship between stable hydrogen and oxygen isotope. The results show that the chemical type of surface water and groundwater was characterized by HCO₃·SO₄-Ca·(Mg) and HCO₃-Ca·(Mg),and TDS of groundwater(318.74 mg·L^-1) was higher than that of the surface water(150.7 mg·L^-1);the dissolution and ion exchange happened during the formation and evolution of surface water and groundwater;the isotopic composition of surface water ranged from -74.05‰ to -61.81‰ for δ¹⁸O and from -11.29‰ to -9.54‰ for δD,while the groundwater(including springs) ranged from -12.74‰ to -9.70‰ for δ¹⁸O and from -89.77‰ to -67.67‰ for δD;the surface water and groundwater have the similar isotopes components and are located near the national precipitation line,indicating that precipitation is the main recharge source of groundwater and surface water. Isotopic composition of surface water is richer than that of groundwater,isotope composition characteristics of surface water and groundwater can be divided into three areas,including surface water zone,groundwater zone,and surface water and groundwater mixing zone,this indicates that surface water and groundwater have different supply sources and a better hydraulic connection with each other. Finally,based on the difference between water chemical index(TDS) and the oxygen isotope distribution,and taken them as the tracer,the transformation relationship between the surface water and the groundwater in the basin was studied. Results show that in the upper reach,Tekes River was mainly recharged by groundwater and southern tributaries,and the branches recharge groundwater;in the middle reach, Tekes River was mainly recharged by groundwater;in lower reach,Tekes River was recharged by Kuokesu tributaries and groundwater. By analyzing the relationship between surface water and groundwater,this study can provide a scientific basis for the evaluation of regional water resources and rational development and utilization of water resources in this region,which has great importance for improving the degree of hydrogeology research in Zhaosu-Tekes basin,and also has certain reference significance for the research of other "vein-like" Rivers.

Key words: Zhaosu-Tekes Basin, groundwater and surfer water, conversion, hydrochemistry, stable isotopes