The extreme service parts represented by aerospace have harsh working environment, complex structure and integrated functions. Multi-material additive manufacturing (MMAM) can meet the macro performance customization and structure function integration in special areas, and has great application potential in nuclear, military, aviation and medical fields. The main factors that influence the interface bonding strength of MMAM technology and the methods to eliminate the defects are introduced. The different powder-feeding methods of MMAM technology and the advantages and disadvantages of each powder-feeding method are introduced. The influence of process parameters on MMAM technology is described. Finally, the current bottleneck problems of MMAM technology are summarized, and the main research directions in the future are prospected.