Abstract: In the process of metal additive manufacturing, the directed energy deposition(DED)method faces the problem of poor forming quality. The temperature and change law of the substrate, powder (or wire) directly affect the component quality in the whole production process. Exploring the law and influence mechanism between process parameters and temperature factor is of great significance. In the application process of technology, the type of processing technology directly determines the forming quality. The main process parameters, such as energy input, temperature control, scanning path and forming shape, also have a significant impact on the forming quality. Making research on process parameters, exploring the mechanism of forming process, and deepening the understanding of additive manufacturing at the micro level will become important research contents and development directions.