Abstract: Addressing the challenges of nonlinear hydrological model parameter calibration easily converging to local optima and the applicability issues of runoff generation mechanisms in semi-arid and semi-humid regions, this study conducts a comparative assessment of the Xin'anjiang Model and the Vertical Mixed Runoff Model using the System Response Parameter Calibration Method (SRPCM), with Rizhao Reservoir in Shandong Province as the case study. An SRPCM optimization framework was established, transforming the nonlinear parameter calibration process into a linear system response solution, effectively overcoming the local optima trap. And it is calibrated and validated using 31 historical flood events. The results demonstrate that: The SRPCM can be effectively applied for parameter optimization in both hydrological models; In the semi-arid and semi-humid region of Rizhao Reservoir, the Vertical Mixed Runoff Model, by incorporating the infiltration-excess runoff mechanism, the simulation accuracy of runoff depth and peak flood discharge of the Vertical Mixed Runoff Model is generally better than that of the Xin'anjiang Model.