As an important second-generation semiconductor material, indium phosphide has wide bandgap, fast electron drift and better radiation resistance than Si and GaAs. It can be used as an alternative material for the preparation of electrical devices on space vehicles. With the nano-size of semiconductor devices, the displacement damage caused by low-energy proton irradiation in space environment is one of the main factors affecting the electrical properties of components. In this paper, the types and proportions of Primary Knock-on Atom(PKA) produced by low energy protons irradiation and the depth distribution of Non-Ionizing Energy Loss(NIEL) of protons with different energies are obtained by Geant4 simulation. The results show that the probability of proton capture and nuclear reaction increases with the increase of proton energy, which decreases the proportion of recoil atoms In and P and enhances other recoil atoms in elastic collision. The NIEL peak tends to move forward in depth of the bulk material with the increase of proton energy, which means the area of serious displacement damage gradually shifts from the end of the material to the surface of the material.