The solution of added mass for water inflow can be summarized as the potential flow solution problem of the corresponding model. Using boundary element method and commercial software to solve UDS (User Defined Scalars) to solve the Laplace equation and obtain the potential flow solution of the corresponding problem. Firstly, the added mass of the plate water entry problem is calculated and compared with the theoretical solution to verify the reliability of the two methods. Furthermore, the added mass of wedges with different deadrise angles was calculated, and the results showed that the added mass values calculated by the two methods were close, while the added mass of wedges increased with the decrease of deadrise angles, gradually approaching the added mass value of flat plates entering the water.