Laser selective melting technology was used to prepare three types of 316L stainless steel lattice structure samples with different porosities and pore sizes. The samples were subjected to quasistatic uniaxial compression tests. The test results showed that, compared with the solid metal structure, the elastic modulus of the lattice structure decreased from 180 GPa to 2 GPa. Furthermore, porosity was found to be the main factor affecting the lattice structure stiffness, and the corresponding numerical relationship was obtained. Under the condition of keeping the overall size and porosity unchanged, the change of lattice size and number was observed to have little effect on the stiffness and yield strength of lattice structure. The finite element model was applied to analyze the macroscopic deformation and stress distribution of the full-size lattice structure and the variation of the micro stress and strain of the single lattice. The printing accuracy of the sample was tested using an industrial CT system. The test show that the diameter of the rod measured perpendicular to the printing direction is greater than that measured parallel to the printing direction. According to the test results of the industrial CT system, the deformation mechanism of lattice structure is obtained.