Abstract: Aba is a region with high altitude, located in the northwest of Sichuan, and at the junction with Qinghai and Gansu provinces. Aba is rich in surface water resources that the Yangtze River and Yellow River both flow across this area. Through systematically sampling the rivers water (76), wells water (7) and streams (8), and analyzing the contents of ¹⁸O, D and trace elements in water, we revealed that ① The contents of D and ¹⁸O in river water of Aba were significantly higher than streams, wells and tap water. Linear correlation analysis indicated that the enrichment of ¹⁸O was closely related to the dissolution of sulfuric minerals; ② There was obvious hydraulic link among well water, tap water and streams in Aba; ③ In Aba, isotopic composition of oxygen and hydrogen in river water of Yellow River system were closing to that of Yangtze River system, which was due to the same rainfall source at the same area; ④ The trace elements of surface water were quite close with the surrounding rocks, with the characteristics of high concentrations of Ba, Zn, Cr, and low concentrations of As, Pb, Cd, which indicated that the trace elements in surface water was mainly affected by the geological background.