Abstract: Theoretical researches on metal additive manufacturing technology and numerical simulation for the technology overseas are reviewed; key points and basic flow in the manufacturing process are introduced,changes of physical properties in the manufacturing process are simply analyzed,and classified discussions are made on three major factors in numerical simulation for the process of metal additive manufacturing,which are temperature field,residual stresses and heat-affected zone; the effectiveness of numerical simulation for the metal additive manufacturing process is confirmed and future work prospects are presented.