As the largest tributary of the Shiyang River, with the average annual inflow of total runoff accounting for 23%, the Xiying River has representative of mountain runoff of inland rivers in the Northwest of China. Using samples collected in this basin from September 2016 to October 2017, the water chemical composition and ion source characteristics of river were studied. The results show that the river is weakly alkaline, the average pH is 8.0 and the TDS is 179.29 mg·L⁻¹. With the elevation decreasing along the river, the TDS of main stream tend to increase first and then decrease, but those of TDS of each tributary decrease, and the latter is lower than the former. Affected significantly by the flow, the lowest value of ion concentration in river occurs in summer, and the highest occurs in autumn and winter. The hydrochemical type of river is CaMg–HCO₃. In the river, the order of cation mass concentration is NH₄⁺ < K⁺ < Na⁺ < Mg²⁺ < Ca²⁺, and that of anion is F⁻ < NO₃⁻ < Cl⁻ < SO₄²⁻ < HCO₃⁻. The sources of ions in river are mainly from the weathering of silicates and carbonates. With the elevation decreasing along the river, the influence of silicates on the inflowing tributaries is gradually strengthened.

西营河作为石羊河最大的支流，年均流入的径流量占总径流的23%，是我国西北内陆河流山地径流的代表。利用2016年9月至2017年10月在该流域采集的样品，研究了河流的水化学成分和离子源特征。结果表明，河流呈弱碱性，平均pH值为8.0，TDS为179.29 mg·L ^-1. 随着沿河海拔的降低，干流的TDS呈先增大后减小的趋势，但各支流的TDS均呈下降趋势，且后者低于前者。受流量影响显着，河流中离子浓度的最低值出现在夏季，最高值出现在秋季和冬季。河流的水化学类型为CaMg-HCO ₃。在河流中，阳离子质量浓度顺序为NH ₄ ⁺  < K ⁺  < Na ⁺  < Mg ²⁺  < Ca ²⁺，阴离子质量浓度顺序为F ^-  < NO ₃ ^-  < Cl ^-  < SO ₄ ^2-  < HCO ₃^-。河流中离子的来源主要来自硅酸盐和碳酸盐的风化作用。随着沿河海拔的降低，硅酸盐对流入支流的影响逐渐加强。