Water quality improvement in the upper reaches of the Yongding River in Zhangjiakou city has become a most significant work for the water safety of the Winter Olympics in 2022. The spatiotemporal variations of surface water quality and the annual flux of main pollutants in the main rivers of Zhangjiakou were studied by the long-term monitoring in Zhangjiakou in the upper reaches of Yongding River from 2013 to 2017. Results showed that: (1) The water quality in the upper reaches of the Yanghe River in Zhangjiakou was good in 2017, while that in the middle and lower reaches was moderately polluted. The water quality in the upper reaches of the Qingshui River was good, while that of the lower reaches was slightly polluted. The water quality in the Sanggan River was good. (2) The differences between the water quality indexes in different rivers were obvious from 2013 to 2017. The variation of water quality in the upper reaches of the Yanghe River was small from 2013 to 2017, while the that of the middle and lower reaches tends to deteriorate. The fluctuations of water quality in the Qingshui and Sanggan rivers were small, and the five-year comprehensive pollution index of the whole basin was 0.82, corresponding to the level of light pollution. (3) The seasonal changes of water quality in the Yanghe and Qingshui rivers were obvious; however, those in the Sanggan River were not obvious. The water quality indexes of the Yanghe River were higher in summer than those in spring and autumn. And the water quality indexes in spring were higher than those in summer and autumn. Total phosphorus and fluoride are the main pollutants in the upper reaches of the Yongding River, with Yanghe River being the main source of contribution. Among them, the contribution rates of total phosphorus and fluoride are 74% and 61%, respectively. Therefore, the local government should focus more on the prevention of phosphorus pollution because the phosphorus was the main factor that can limit water pollution. Once the water is polluted by phosphorus, it will be very difficult to be remedied.