Abstract: In order to study the water chemistry characteristics and ion sources of surface water in the Chan River basin during the flood season and to add suggestions to rationalize local water resources management, a total of 10 surface water samples were collected from the Chan River basin and combined with spatial distribution maps, Piper triangles, Gibbs plots and ion correlation analysis to analyze the water chemistry characteristics, spatial variation characteristics, major ion sources and controlling factors in the Chan River basin. The results show that the Chan River basin is weakly alkaline during the flood season, with mean TDS values lower than the mean values during the dry season in the same basin but higher than the global river mean values. The dominant cations are Ca²⁺ and Na⁺, the dominant anion is HCO₃⁻, and the water chemistry type is dominated by Na-HCO₃, with an overall trend of low southeast to high northwest content of the major ions. The Chan River basin is mainly controlled by the weathering of silicate rocks and is subject to the influence of evaporite dissolution. In order to address the water shortage issue in Xi'an, we must simultaneously exploit and safeguard source water, develop midstream water for industrial use, prevent pollution events in downstream water, and utilize water resources intelligently.