Al-Si alloys prepared by selective laser melting (SLM) have great potential in the development of aerospace materials customization and lightweight. However, corrosion behavior affecting the life of SLM forming parts has not been widely concerned. Based on current literature reports, this paper analyzed the formation reasons for metallurgical defects and microstructure according to solidification characteristics in the SLM process. Combined with the corrosion mechanism of traditional casting Al-Si alloy in chlorine compounds, the corrosion mechanism of Al-Si alloy prepared by SLM was further discussed. The effects of metallurgical defects, microstructure, and heat treatment on corrosion behavior are summarized. It is found that the relative density, surface topography (roughness) of the sample, eutectic Si content, morphology, and distribution has important effects on corrosion performance. On this basis, it is pointed out that the existing technological parameters in the corrosion research of Al-Si alloy under the SLM process are not systematic, the effects of Mg, Fe, and other elements are ignored, the research methods and scope are not perfect, and the future development direction.