The structure of plunge pool is a key factor influencing energy dissipation of high dams, and the optimization of bottom plate type is crucial to effectively increasing the stability of the bottom plate and decreasing hydrodynamic load. Flat bottom and inverted arch types are widely used as two common plunge pools; however, the comparative study of hydrodynamic load characteristics between these types is rare. Based on the 1∶50 integral model of Baihetan Hydropower Station, the characteristics of average pressure and fluctuating pressure of flat and inverted arch plunge pools are compared using physical model test. The results show that the peak value of average pressure of inverted arch is smaller than that of flat bottom, so is the lowest value in flow direction. The difference of peak values of fluctuating pressure is negligible. The overall pressure fluctuation of inverted arch is larger than that of flat bottom; however, the gradient of the fluctuating pressure of inverted arch is smaller than that of flat bottom.