Abstract: Pore defects can cause the appearance of cracks, which is one of the main reasons for the failure of aluminum alloys in additive manufacturing. The formation of pores is due to differences in the solubility and volume shrinkage of hydrogen atoms during the solidification process of the molten pool. Compared with traditional processes, the use of arc additive technology can effectively control the porosity of aluminum alloys. Based on this, the influence of process parameters on pore rate, including process conditions, wire delivery speed, welding speed, protective gas composition and flow and other main factors, was elaborated. The influence of these parameter changes on the porosity was analyzed from a microscopic perspective. Subsequently, the mainstream methods used in the simulation of porosity during solidification process, cellular automata and phase field method, were introduced. These two methods summarized the main achievements in the study of porosity formation mechanism. Finally, the future research directions for reducing the porosity in aluminum alloy arc additives were prospected.