The molecular dynamics method is used to simulate the cascade collision of 4H-SiC material with hexagonal crystal structure by using LAMMPS code. 4H-SiC crystal structure model is established and the evolution of radiation-induced point defects by the collision cascade is simulated at different primary knock-on atom (PKA) energy and initial incident direction. The simulation results show that the total point defects include vacancy defects, interstitial atoms and antisite defects, giving priority to vacancy defects and interstitial. The space distribution of vacancy defects and interstitial atoms is given, in which the number of vacancy defects produced by cascade collision has linear relationship with PKA energy, the space distributions of vacancy defects and interstitial atoms, especially the gathered area of vacancy defects and interstitial atoms, has a close relationship with PKA energy. The above results provide a theoretical basis for the analysis of electrical properties change of electronic devices with 4H-SiC substrate under irradiation environment.