Water samples were collected and analyzed respectively at nine sampling sites along Zhengzhou section of Jialu River in July(water diversion time)and in September(no water diversion time), and then comprehensive water quality identification index method and factor analysis were applied for the evaluation of water quality and apportionment of pollution sources respectively. The results showed that the comprehensive water quality of the upper reaches of the Zhengzhou section of the Jialu River was of level II or III, the water quality of the mid-stream Lakes was classified as IV level, and the downstream water quality was classified as IV to worse than V level; the water quality of Suoxu River and Qili River were worse than V level, worse than V level and black smelly water, respectively. Water diversion from Yellow River to the Jialu river through Yangqiao main canal can only change the water quality of the nearest receiving area temporarily, with no obvious impact on the water quality of Zhengzhou section. Two factors can explain the information of 5 water quality indicators. In the lower reaches of the main stream and the tributaries, the representative indices TN, TP, NH⁺₄-N of the first pollution factor are mainly related to the drainage of the municipal sewage treatment, while the representative indexes of the second pollution factor, COD_Cr and COD_Mn, are mainly related to the untreated sewage. The pollution of upper and middle reaches of the Jialu River are mainly non-point source pollution and endogenous pollution.