In order to study the effect of strut diameter difference on the compression performance of body-centered cubic (bcc) lattice structure, five bcc-x lattice structures with different strut diameters were designed under the same density. 316L stainless steel with bcc-x lattice structures were fabricated by selective laser melting technique. A finite element analysis model of quasi-static compression of the lattice structure was established using the plastic constitutive model of the material. The experimental and finite element simulation results show that with the increase in strut scale factor x, the compressive performance of bcc lattice shows a trend of first increasing and then decreasing, and when x is greater than 1, the compressive performance is more sensitive to x. When x is equal to 1, the optimal compressive properties can be obtained. The specific stiffness, specific strength and specific energy absorption of bcc-1 are 986.794 MPa·cm³·g^-1, 25.084 MPa·cm³·g^-1 and 11.731 J/g, respectively. Compared with bcc-1, both the decrease and increase of x will destroy the axial symmetry of the cell, and the larger the x deviating from 1, the more irregular the distribution of high stress regions between layers, and the more unstable the deformation of the structure. The compressive performance of bcc-1.5 is the worst, and the specific stiffness, specific strength and specific energy absorption are reduced by 20.765%, 12.265% and 12.309%, respectively, compared with those of bcc-1.