Control of non-point source pollution becomes an important part of pollution control in East Liao River Liaoyuan segment. In this paper, average daily pollution load of dry season is used to revise the runoff division method. And the revised method is applied to estimate the non-point COD and ammonia nitrogen’s load in East Liao River Liaoyuan segment. Pearson correlation coefficient is also calculated to analyze the correlation between non-point source pollution load and precipitation. The results show that non-point source pollution changes a lot in different year and different month. Non-point COD accounts for about 50-65%, while non-point ammonia nitrogen accounts for about 30-50%. Therefore, the East Liao River Liaoyuan segment is heavily polluted. The inter-monthly non-point source pollution also changes a lot. Non-point COD mainly occurs in July and August, which is caused by rainfall in summer. Non-point ammonia nitrogen mainly occurs in March and July, which is caused by snowmelt in spring and rainfall in summer. Non-point source pollution and precipitation have a strong correlation.