Abstract: Instantaneous high overload that appears during projectile's launch process always results in the failure of spinning micro-machine's rotating rack used for trajectory correction fuse, rendering the fuse unable to work normally. In view of such a problem, combined with the design method of resisting overloads for onboard device, based on the rotating rack's dynamic model and bearing's energy absorption principle under the condition of buffer design, the bearing's overload characteristic was acquired through finite element dynamic simulation based on projectile-barrel-fuse coupling with the operating characteristic of machine's rotating rack concerned. The results indicated that the axial inertial force was the main load imposed on bearings. On this basis, two schemes, adding the buffer made of copper and changing the size in shaft shoulder and bottom bolt, were proposed. Then the ball bearings's maximal stress variation during projectile's launch process was acquired by finite element dynamic simulation based on projectile-barrel-fuse coupling. The results indicated that the buffer cannot reduce the maximal stress to below the bearing steel's yield strength. However, the bearings's maximal stress can be reduced to below the bearing steel's yield strength. Through determination of thrust bearing's deformation, this scheme can meet the needs of resisting overloads in the design of the rotating rack, and ensure normal operating of the micro-machine's power generation after launch process.