The invention discloses a 304/304L stainless steel selective laser melting forming method. The method comprises the following steps of (1) charging stainless steel spherical powder into a powder supply cavity of a 3D printer; (2) introducing protective gas into a forming chamber; (3) evenly laying the stainless steel spherical powder with the thickness less than 50 microns on a base plate in advance; (4) establishing and pre-preparing a stainless steel sample three-dimensional model, placing the three-dimensional model in place, conducting hierarchical processing on the three-dimensional model, inputting hierarchical data subjected to hierarchical processing into laser scanning path generation software to generate s print file; (5) scanning the stainless steel spherical powder laid in advance through a laser device to form a smooth stainless steel molten layer, dropping the base plate by a set distance, paving the stainless steel molten layer with stainless steel spherical powder withthe same thickness as the dropping thickness of the base plate again and scanning the laid stainless steel spherical powder to obtain a smooth stainless steel molten layer; and (6) repeating the step(5). The 304/304L stainless steel selective laser melting forming method has the advantages that the cycle is short, and material losses are less.