Based on the theory of pressure wave, analysis of Numerical Fitting-point has been applied to study the effect of hydrodynamic pressure from silt depth, reflection boundary and bedrock feature for arch dam. It showed that silt stratification may produce explicit depression effect on hydrodynamic pressure of dam surface and decrease the seismic motion at some extend, absorbability effect of submarine boundary can too reduce the peak value of hydrodynamic pressure of dam surface.
