Abstract: Based on the Lagrange finite element method, briefly introduce a computational technique for sliding interface treatment in 3D oblique penetration. The slave elements used in conventional computations are abandoned, and at the same time the slave nodes are advanced. Thereby, the difficulties such as the master-slave element intersection, the sliding interface recognition, modification and redefinition encountered in 3D oblique penetration simulation calculations are avoided to insure high computational precision and efficiency. Numerical computations for the ogive-nosed steel rod penetrating into the aluminum target show that the computational results are in good agreement with the experimental results for both normal and oblique penetrations. Therefore, the method discussed and the program developed are reasonable and effective, and they are resultful for the numerical study on penetration and perforation.