This work examines the effect of linear and volumetric energy densities on the printing of TC4 titanium alloy using selective laser melting. With an increased linear energy density, the width of the molten pool increased rapidly at first and gradually converged to a maximum value of 122 μm. Meanwhile, the height difference of the melted track decreased from 27 μm to 18 μm and then increased to 28 μm. Owing to the apparent and forming densities, the given powder thickness of 30 μm cannot represent the real powder thickness, which was re-evaluated to be 55 μm by the numerical model in this work. The re-evaluated powder thickness was then applied to calculate the volumetric energy density quantitatively. By comparing the relationship between the linear and volumetric energy densities with the surface roughness and efficiency of space filling of cube samples, it was observed that volumetric energy density can be used as a process parameter to evaluate three-dimensional printing quality.