In this study, we investigate the influence of the forming process on the types, sizes, and quantities of internal defects in a GH3536 alloy fabricated via laser selective melting. We test the microstructure, density, and defect quantity, along with the defect type, size distribution, and quantity of the alloy. The research shows that a change in the process parameters gradually increases the energy density, with the density of the formed parts gradually increasing before stabilizing. The sample is uniform and dense without defects within 79.17?92.59 J/mm³ of the energy density. With the gradual increase or decrease in the energy density, the internal defects of the sample are mainly pore-type defects with a pore size <0.1 mm. When the energy density ≤48.87 J/mm³, non-fusion and micro cracks primarily constitute the internal defects of the sample.