Herein, V₈C₇ nanoparticles were mixed with 316L stainless steel powder via ball-milling for selective laser melting (SLM)-assisted three-dimensional (3D) printing. Then, a lattice structural V₈C₇/316L composite was printed via SLM. Using optimized SLM process parameters, the density of composite solid parts as high as 99.4% was achieved. In addition, during the laser melting-solidification process, VC_x reinforcements were generated via the decomposition-precipitation mechanism of V₈C₇ as the nanoscale nucleation sites. Consequently, the dispersed VC_x nanoparticles were preferentially distributed along the austenite grain boundaries, thereby further inhibiting the grain-coarsening of austenite during rapid solidification. The nano-VC_x reinforcements and the ultrafine metal-matrix grains that were nearly equiaxed, contributed to a significant increase in the specific strength of V₈C₇/316L lattice structures.