<p>Selective laser melting (SLM) technology, a widely applied additive manufacturing technique, demonstrates significant advantages in the fabrication of complex, porous metal components. This study systematically investigates the process optimization and anisotropic compressive performance of body-centered cubic (BCC) lattice structures of AlSi10Mg alloy produced by SLM. The results indicated that a high-quality forming with a relative density exceeding 99.7% was successfully achieved by precisely controlling the SLM process parameters, and the optimal volumetric energy density range was determined to be 35.7–47.6&#xa0;J/mm³. The microstructure showed notable heterogeneous, consisting of α-Al dendrites and eutectic Si networks, including fine grain, coarse grain, and heat-affected zones. Remarkably, the BCC lattice structure exhibited pronounced anisotropic compressive behavior. The compressive performance and energy absorption characteristics along the build direction were superior to those along the horizontal direction. Additionally, the difference in elastic modulus expanded from 2.5 to 17.9% as the porosity increased from 70 to 85%. Fracture mode analysis revealed that compression along the build direction resulted in a 45° shear fracture, whereas compression along the horizontal direction exhibited a layer-by-layer fracture characteristic. Furthermore, based on the Gibson-Ashby model, empirical relationships were established between the relative elastic modulus, yield strength, and relative density of the AlSi10Mg BCC lattice structure in different directions. This study contributes to a deeper understanding of the structure-property relationships of BCC lattice structures fabricated by SLM, providing valuable theoretical insights and process guidance for the design and application of lightweight structural components.</p>