To quantify the impact of terrestrial nitrogen and phosphorus pollution on the marine environment in the northern Liaodong Bay, the Hun River and Taizi River Basin(Hun-Tai River Basin) in the northern Liaodong Bay were taken as the research objects. A SWAT model was constructed to simulate the generation and influx of terrestrial nitrogen and phosphorus pollution loads from 2015 to 2018. And then the inter-annual and intra-annual variation characteristics of the pollution loads were analyzed to investigate the sources, contribution rates and driving factors of the nitrogen and phosphorus pollution. The results indicated that the overall generation and influx of terrestrial nitrogen and phosphorus pollution exhibited a decreasing trend year by year (excluding 2016), and the nitrogen and phosphorus influx of the Taizi River was approximately 2.4 times of that of the Hun River. Driven by precipitation, the proportion of total phosphorus and ammonia nitrogen influx during the wet season exceeded 55%. Total phosphorus and ammonia nitrogen contributed significantly to the influx pollution, and the correlation between the influx and pollutant concentration was much lower than that between the influx and inflow volume. Therefore, strengthening pollution control in the Hun-Tai River Basin and reducing the influx of nitrogen and phosphorus from the source is the key to addressing marine pollution issues in the northern Liaodong Bay.