Affected by the unique geographical environment and climate, the hydrological cycle and the underlying mechanisms of the occurrence, migration, and transformation of non-point source pollution are more complicated in semi-arid and semi-humid watersheds. Non-point source pollution models are effective means for quantitatively describing the complex hydrological cycle and the process of pollutants migration and transformation, and thus served as important tools for watershed ecosystem management. Based on the unique climate, hydrological characteristics, and underlying surface conditions in semi-arid and semi-humid areas, we elaborated on the occurrence mechanism of non-point source pollution, and summarized the status, progress, and shortage of the research and application of solving water environmental problems by using non-point source pollution models. Moreover, the scheme for constructing non-point source pollution models applied to semi-arid and semi-humid areas was put forward. Finally, we discussed the development trend of non-point source pollution models.