The reduction of pollution load is a critical indicator for evaluating the effectiveness of water ecological restoration. However, measuring the pollution load is complex. And the pollution load is influenced by various factors, including environmental, chemical, physical, and human activities. Among these factors, environmental conditions have a relatively significant impact. Therefore, this paper utilizes numerical simulation to investigate the differences in pollution load reduction under different environmental conditions (such as rainfall, wind, etc.) compared to an ideal state without any environmental factors. By analyzing relevant conditions, the research summarizes the pollution load impact coefficients of different environmental factors, providing a theoretical basis for measuring pollution load under abnormal weather conditions in water ecological restoration projects and offering a scientific reference for determining water quality categories.