In order to resist the impact of aircraft crash, Reinforced concrete (RC) or Steel plate concrete (SC) structures are usually used in the design of external walls in nuclear island buildings. For comparing the im-pact resistance performance of the above two types of structures, comparative simulation analyses of a group of 1/7.5 scale aircraft model impact tests are carried out by applying nonlinear finite element code AN-SYS/LS-DYNA based on force time-history analysis method in this paper. The damage modes of the walls and the residual velocity of the scattered debris and the deformation of rear-face steel plate calculated by this paper are compared to the impact test results and the results based on the missile-target interaction analysis method of RC and SC walls, respectively. Of course, it is important that the simulation results with the same thickness walls of different types (RC/HSC/FSC) are compared either. The results indicate that the FEM si-mulation results based on the force time-history analysis method are in good agreement with the test results and the impact resistance performance of SC walls is better than RC walls, especially the rear face steel plate is very effective in preventing the perforation and scabbing of concrete. Therefore, the thickness of SC structures can be reduced in important structures like nuclear power plants against impact of aircraft com-pared to RC structures.