The metal materials manufactured by laser selective melting technology have better mechanical properties than traditional casting materials and are suitable for the manufacture of various complex parts. However, the defects introduced in the process implementation are the main factors restricting the fatigue properties. Therefore, the mechanical performance of the SLM prepared 316L stainless steels was assessed. The results show that the tensile strength, yield strength, and elongation of 316L stainless steel formed by laser selective melting process are 816.8, 720.4 MPa, and 33.83%, respectively, which are much higher than that of the forged parts. However, it is found that the measured data of fatigue life are much dispersed due to the initiation of cracks on defects in the surface and/or near-surface during fatigue testing. The reference S-N curve of the material was obtained by the maximum likelihood method, and the fatigue limit was predicted to be 259 MPa. At the same time, combined with the √area parameter and the extreme statistical method, the maximum defect and fatigue limit of the material was predicted. The error between the fatigue limit prediction results and the test results is less than 10%, which provides a partial safety estimation method for the safety evaluation of the material.