In order to study the spatio-temporal variations and potential pollutant sources of the water quality of the upper reaches of the Zhanghe River, the multivariate statistical approach was used to analyze the measured data of 25 water quality parameters at 20 different cross-sections of the upper reaches in 2013. The results demonstrated that the water quality of the upper reaches of the Zhanghe River was classified into two distinct clusters: cluster A, which has good water quality and is close to water source and river sections with adequate water, and reservoirs; and cluster B, which has heavily polluted water and covers the middle and lower reaches of the south source and mainstream of the Zhuozhang River. The main pollutants of cluster B were heavy metals and nutrients, indicating that cluster B was influenced by heavy industrial pollution. The inner-annual variation of water quality had two periods: period I(from January to March)with worse water quality, and period II(from April to December)with better water quality. The organic pollution mainly occurred in period I, and six main pollutant sources were identified.