Abstract: Finite element analysis software ABAQUS was used to establish a two-dimensional plane simulation model of polyurethane coating micro-indentation test process in order to obtain the load-displacement curve of polyurethane coating material. A three-dimensional model of sphere impacting polyurethane coating of steel structure was also established by the sortfware to study the effects of polyurethane coating thickness on the energy conversion coefficient, time history of contact impact force and residual stress in the target material under impact loads. The results show that as the coating thickness increased, the energy conversion coefficient first increased and then decreased. When the coating thickness was 0.2 mm, the energy conversion coefficient reached a maximum of 0.943. The coating had a more obvious impact mitigation effect which increased with the increase of coating thickness. The residual stress of uncoated steel plates and steel plates with a coating in thickness of 0.2 mm was relatively large, when the coating thickness was greater than 0.4 mm, the stress was relatively small. The optimal thickness of the coating was 0.8 mm, which had a yield strength of 1.86 MPa.