The representation of runoff generation is a core component of hydrological process modeling. Hybrid runoff models, which integrate both saturation-excess and infiltration-excess runoff mechanisms, are considered more comprehensive and better representatives of actual runoff processes. However, the quantitative impacts of different hybrid runoff models on runoff simulation in arid and semi-arid regions remain unclear. This study employs numerical experiments and watershed hydrological modeling to analyze the differences in runoff generation calculations caused by structural variations among different runoff models. Three hybrid runoff models were coupled with the VIC-CAS model to compare their daily runoff simulation performance in two basins in northwest China. The results reveal that runoff calculations in hybrid runoff models are influenced by both rainfall intensity and soil moisture. When rainfall intensity exceeds the soil infiltration capacity, hybrid runoff models increase total runoff due to the generation of more infiltration-excess runoff, particularly under low soil moisture conditions. Daily discharge simulations in the study watersheds show that hybrid runoff models and saturation-excess runoff models perform similarly under snowmelt, ice melt, and low-intensity rainfall conditions. However, during high-intensity rainfall events, hybrid models better capture peak flow, while saturation-excess runoff models underestimate peak flow due to the neglect of infiltration-excess runoff. In snowmelt-dominated watersheds, seasonal runoff patterns are observed: the snowmelt runoff process resembles the saturation-excess mechanism in spring, whereas it exhibits characteristics of the hybrid runoff mechanism during heavy rainfall events in summer. Hybrid runoff models demonstrate greater potential for simulating peak flow and are better suited to adapt to changes in surface water input forms and intensities in arid and semi-arid regions, showing greater robustness. Additionally, accurate representation of rainfall intensity is critical for calculating infiltration-excess runoff in hydrological modeling. This study underscores the importance of hybrid runoff models in improving the physical basis of runoff mechanisms and reducing simulation uncertainties, providing valuable insights for hydrological modeling in arid and semi-arid regions.