The porous Ti-6Al-4V alloy structures with different pore sizes and porosity are fabricated by selective laser melting aiming at the problem of stress shielding existing in the Ti-6Al-4V alloy implants. In addition, the relative densities, molding precision, microstructures, compression properties and elastic moduli of different porous samples are characterized. The results show that the microstructures of the as-built porous structures are composed of fine needle α' martensite phases. As for the porous Ti-6Al-4V alloy structures with deferent relative densities, when the relative density increases from 0.420 to 0.548, the elastic modulus increases from 15.1 GPa to 25.7 GPa, and the compressive strength increases from 223 MPa to 352 MPa. Moreover, the relationship of elastic modulus and compressive strength with relative density satisfies well with the Gibson-Ashby model. In addition, the compression fractures of porous Ti-6Al-4V alloys occur at the junction of struts. The angle between the fracture and the horizontal direction is about 45° and the fracture mode is a brittle one.