Abstract: Taking the dynamic compression mechanical properties of polyurea as the research object, a simplified three-line elastic-plastic constitutive model is proposed, considering dynamic elastic modulus, dynamic intensity factor and dynamic tangent modulus. Based on ANSYS/LS-DYNA software, the compression finite element model of polyurea under different grade strain rates are established and compared with tests. The research results show following characteristics: The dynamic elastic modulus increase factor, dynamic intensity factor and dynamic tangent modulus factor increase regularly with the increase of strain rates, and the relationship is bilinear with the logarithm of strain rates. At low and intermediate strain rates, the slopes of the linear relationships are gentle; at high strain rate, the slopes of the linear relationships are steep, the slope of the dynamic increase factor of elastic modulus is greater than that of the dynamic intensity factor, and the slope of the dynamic tangent modulus factor in the second stage is the same as that of the dynamic intensity factor, but the slope of the dynamic tangent modulus factor in the third stage is about 2.3 times that of the dynamic intensity factor, it shows that the late stress strengthening effect of polyurea under high strain rate is more significant. The simplified three-line elastoplastic constitutive model of polyurea can be better realized in ANSYS/LS-DYNA. The finite element model established can simulate the compression test of polyurea, and further verifies the effectiveness of the simplified elastoplastic constitutive model under compression loading with different strain rates. The analysis might provide the material model parameters basis for the finite element model of polyurea coating reinforced protective structure.