Selective laser melting (SLM) is used to rapidly form 316L stainless steels formed when the laser rotation angle is 73° and the powder layer is 30-μm thick, and the effects of bulk laser energy density and forming direction on the anisotropy of microstructure and mechanical properties of the formed parts are studied. The results show that the forming direction has a great influence on the mechanical properties, and the anisotropy of the mechanical property varies with the anisotropy of the microstructure. As the bulk laser energy density increases, the surface of the molten pool tends to be flat, the grain growth directions of formed part become singular in the x and y directions, and the grain growth direction of formed part in the z direction is obviously orientation-dependent. When the bulk laser energy density is 65-85 J·mm ^-3, the crystal growth direction is well aligned with the stacking direction, and the tensile strength and the percentage elongation after fracture are optimal. Therefore, the bulk laser energy density can be used for controlling the microstructure and mechanical properties of formed parts.