© 2020 Tech Science Press. All rights reserved. The internal structure of the inertial measurement unit (IMU) in active state is easily damaged in the high overload environment. So that the IMU is usually required to be powered within the disappearance of the high overload. In this paper, a mechanical switch is designed to enable the IMU based on the analysis of the impact of high overload on the power-supply circuit. In which, parameters of mechanical switch are determined through theoretical calculation and data analysis. The innovation of the proposed structure lies in that the mechanical switch is triggered through the high overload process and could provide a delay signal for the circuit. After all, the proposed switch is tested through mechanical simulation, impact test and practical test. The experimental results show that the designed mechanical switch can effectively and reliably provide the delay for the circuit and guarantee operation of the IMU under high overload.