Abstract: In order to clarify the reliability issues of 3D integrated structure microsystem under high overload environments, a stress characteristic analysis of 3D integrated structure microsystem under high overload is carried out. A structural model of the three-dimensional stacked integrated microsystem is established, and it is analyzed and verified through finite element simulation analysis and impact testing. The stress magnitude and stress distribution in different structural areas of the microsystem under three vertical axis overload impacts are analyzed, and the weak and prone failure parts of the microsystem structure are identified. The microsphere structure is studied with a focus on the influence of microsphere structure size, material, and bottom filling on reliability, and the direction of structural optimization is clarified. And the reliability of the stacked integrated microsystem after filling is verified through impact testing, providing guidance for improving the reliability of 3D integrated structure microsystem under high overload impact.