Abstract: Firstly,the research and application status of 3D printing technology at home and abroad and the characteristics of laser selective melting technology were described.Then,taking the aluminum alloy thin-wall parachute box in the field of aerospace manufacturing as a typical case,around the key point of how to control the variable part shape to ensure the quality in the laser selective melting process,the application research was carried out from the aspects of adding auxiliary support,process parameter setting,annealing heat treatment,three-dimensional scanning detection and so on.Finally,it is shown that the deformation and other defects in laser selective melting can be reduced by scientific design auxiliary support,reasonable setting of process parameters and standardized heat treatment.