Gradient lattice structure is now commonly used as energy-absorbing components in aerospace, national defense and medical fields due to its excellent energy absorption ability when compressed. However, with the development of modern industry, the engineering field has put forward higher requirements on its compression properties. To make it further optimized, it is necessary to study the relationship between cell, structural parameters and compression properties. Therefore, in this study, two AlSi10Mg rod-diameter-change gradient body-centered cubic (BCC) and diamond (Diam) structures with different gradient gap were formed by selective laser melting (SLM) to investigate the effect of gradient gap on the compression properties, and to compare the two cells. The results of quasi-static uniaxial compression experiments and finite element analysis (FEA) show that the absorbed energy per unit volume increases significantly with the increase of gradient gap at the same relative density and with the same cell. The compressive modulus, yield strength, compressive strength and peak stress of Diam gradient lattice structure are higher than those of BCC when the gradient gap is the same, and its absorbed energy per unit volume and energy absorption efficiency are also higher than those of BCC.