本文采用Lagrange方法给出了具有倾斜承压面的刚性坝地震时所承受的动水压力。计算结果表明:对于垂直坝,本文结果精确符合Westergaard的结果;对于不同倾角的斜坝,本文结果较好地符合Zangrf和Haefeli的实验结果,本方法还适用于计算计及自由面波动影响的非线性动水压力, In this paper, we use the Lagrange method to give the hydrodynamic pressure experienced by a rigid dam with an inclined pressure surface. The calculation results show that the results of this paper are exactly in accordance with Westergaard’s results for vertical dams, and for the inclined dams of different inclination angles, the results of this paper are in good agreement with the experimental results of Zangrf and Haefeli. This method is also applicable to the calculation of non-fluctuating effects of free surface. Linear hydrodynamic pressure,