A model was created to predict runoff in mountainous areas of northwest China. By using data on temperature and precipitation, the model can forecast monthly runoff. The study focused on a specific watershed in the Heihe River basin and found that in wet years, there is more precipitation, evaporation, and runoff. However, the proportion of glacial and snow meltwater to total runoff decreases. This means that ice and snow meltwater help regulate runoff. The model accurately predicted annual runoff and monthly distribution, making it useful for managing water resources in arid regions.