Abstract: Due to the characteristics of light, high strength and adjustable mechanical properties of porous structure, it is widely used in bone medicine, aerospace and other fields. In order to explore the forming error and compression failure performance of porous structure with selective laser melting (SLM), this paper takes two kinds of porous structure with diamond lattice and spherical six-hole opening as examples to study the compressive mechanical behavior of porous structure manufactured by SLM by theoretical prediction and experimental test. ANSYS software was used to simulate the quasi-static compression of the studied porous structure, and the uniaxial compression experiment of the SLM formed porous structure was carried out. Finally, the deformation process and failure mechanism of the SLM formed porous structure were observed and analyzed combined with the simulation and experiment. After comparison, it is found that the size of the numerical design porous structure deviates from that of the final manufactured structure, resulting in a certain difference between the theoretical value of mechanical properties and the experimental value, but the variation law of stress and strain field is consistent. The experimental results show that when the porosity is 50% ~ 80%, the yield strength and elastic modulus of diamond lattice structure are 31.85 ~ 182.13 MPa and 1.45 ~ 2.30 GPa respectively. The yield strength and elastic modulus of six-hole spherical structure are 35.19 ~ 130.64 MPa and 1.59 ~ 2.90 GPa respectively. The mechanical properties of different porous structures vary with the increase of porosity.