The BCC 316L porous structure is prepared based on the LPBF technology. The compression process of this porous structure mainly experiences the elastic stage, platform stress stage and densification stage. By observing the morphology and measuring the geometric parameters of the porous structure, when the diameter of the rod is from 0.4 mm to 1.2 mm and the volume fraction is from 4.9% to 35.75%, the relative errors of diameter and volume fraction are from 15.00% to 6.08% and from 8.20% to 6.03%, respectively. It can be seen that the forming effect is good, and the contour error and surface sticking are the main causes of the error. The larger the size, the higher the forming accuracy. With the increase of rod diameter, the equivalent elastic modulus increases from 59.87 MPa to 3356.21 MPa, and the compressive yield strength increases from 1.02 MPa to 33.88 MPa. The research conclusions of the finite element analysis and the mechanical test are compared and analyzed. The average relative error of equivalent elastic modulus obtained by the finite element analysis and the mechanical test is 9.11%, and the average relative error of compressive yield strength is 7.86%. Both are within 10%. Therefore, the finite element model can effectively predict the mechanical properties of the 316L stainless steel body-centered cubic porous structure within a certain error range.