Based on the 8 indicators of 8 monitoring sections of 8 main rivers entering Taihu Lake from 2020 to 2022, the temporal and spatial differentiation characteristics of pollution in the main rivers entering the lake were analyzed and discussed, and the positive definite matrix factor analysis model was used to analyze the pollution sources. The results showed that: 1. The concentration of pollution indicators in the rivers entering the lake decreased year by year; The concentrations of NH3-N and TN were higher in winter (January-February and December), the concentrations of CODMn and TP were higher in summer (June-September), and the concentrations of COD and BOD5 peaked twice a year (January-May and June-September). 2. The concentration of pollution indicators in the southern part of Taihu Lake, Wangyu River and Xiaoxigang, and Dagang River in the southwest mountainous area are at a relatively low level. The concentrations of pollution indicators in Wujin Port, Taizhu Canal, Taiyun South Canal, Dapu Port and Wuxi Port are relatively high, which contribute greatly to the N and P of Taihu Lake. 3. There are four main types of pollution sources in Taihu Lake, namely livestock and poultry breeding and planting, production and living, industry and aquaculture, with contribution rates of 42.1%, 12.9%, 25.2% and 19.8% respectively. Agricultural non-point sources have a great impact on water pollutants, and the amount of pollutants entering rivers should be reduced according to the water withdrawal paths of livestock, poultry, aquaculture and farmland. In this study, the sources of pollutants entering the river were quantified, and the results of the study could provide a scientific reference for the treatment of Taihu Lake water body.