The geological conditions of the sea sluices in Shanghai are often poor, which generally have the characteristics of poor foundation bearing capacity and strong foundation soil permeability. The anti-seepage measures should be set up in sluice projects to save seepage.The traditional seepage calculation method is generally improved resistance coefficient method.This method is conservative. For complex structures, it is unable to quantify the seepage calculation results of each part of the sluice foundation, especially the lateral seepage of the sluice.The appearance of three-dimensional finite element method is very helpful to the seepage calculation of sluice foundation. Taking Luchaogang sluice as an example, this paper compares the three-dimensional finite element method with the improved resistance coefficient method, and calculates the seepage and lateral flow around the sluice foundation respectively, and obtains accurate and reliable calculation results.