Three-dimensional finite element simulation is used to investigate the temperature field with the island scanning strategy paralleled with the S-shaped scanning strategy. Considering the influence of heat conduction, heat radiation and heat convection, nonlinear relationship between thermophysical properties of metal material and temperature, and enthalpy processing utilizing latent heat of phase change, we established a finite element model of metal selective laser melting (SLM) is established. It is found that the molten pool is in the shape of a water droplet, and the temperature contour at front-end is denser than that at back-end. Compared with the S-shaped scanning strategy, island scanning has the phenomenon of secondary temperature elevation at the island edge. The whole temperature field of the model is uniform, which is beneficial to reducing the stress concentration. It was observed that the average width of the β phase in the samples built with the island scanning strategy is significantly larger than that with the S-shaped scanning strategy. The influence of the island scanning on the boundary of the islands is quality of overlapping areas, and the overlap between adjacent islands is poor.