In order to explore the dynamic response of UUV in the cross-media process,the numerical calculation model of UUV is established based on the Arbitrary Lagrange-Euler (ALE) algorithm. The influence of different initial parameters on the cross-media impact load of UUV is simulated and analyzed. The functional relationship between the maximum impact load and the cross-media velocity and the cross-media angle is given. The research results can provide a reference for the cross-medium trajectory and structure design of UUV.