Considering the high temperature gradient and rapid cooling rate in selective laser melting technology (SLM) forming process, this paper initially expounds the time consuming and consumption problems of heat treatment method in solving residual stress, deformation, pore defects and other properties. Based on the potential advantages of remelting scanning in SLM process, the similarities and differences of forming performance between initial scanning and remelting scanning were systematically studied. Based on the 3D surface morphology and surface roughness, the surface quality of Ti6Al4V alloy under initial scanning and remelting scanning was analyzed. In combination with the internal pores, the internal quality differences and similarities of Ti6Al4V alloy under initial scanning and remelting scanning were analyzed. The similarities and differences of microstructure and mechanical properties of Ti6Al4V alloy under initial scanning and remelting scanning were analyzed in combination with microstructure and tensile properties. The results show that the microstructure of the upper surface is martensitic needles α′, and the microstructure of the side surface is columnar grains β, and these columnar grains β pass through the multilayer solidification layer. However, the breadth of these columnar grains β varies between the two scanning methods. Additionally, the tensile strength of remelting scanning is better than that of the initial scanning. In the fracture morphology of remelting scanning, the microstructure becomes larger and the number of dimples decreases.