The 3DSPH-SHELL coupling algorithm based on finite element method and smooth particle hydrodynamic method has been proposed to solve the distortion problem of thin-walled structures during numerical simulation. The simulating of one-dimensional wave propagation has been carried out to verify the precision of 3DSPH-SHELL coupling algorithm. Then, the simulating of elastic steel plate under low-velocity impact, the Taylor test and projectiles penetrating steel plate has been calculated by using the 3DSPH-SHELL coupling algorithm. The simulation results agree well with both the theoretical values and the experimental results. The results show that the 3DSPH-SHELL coupling algorithm is accurate and efficient and can better reappear the local physical details. So the 3DSPH-SHELL coupling algorithm is suitable for the simulation of impact of thin-walled structures.