Electromagnetic self-locking valves are widely used in spacecraft， such as satellites， launch vehicles， and spaceship. In strong impact environments， such as engine ignition， explosion of pyrotechnic devices， and separation of rockets， locking failures of self-locking valves may occur， which can affect the safe operation of the spacecraft. Aiming at the locking reliability of the electromagnetic self-locking valve under impact load， the paper studied the locking failure mechanism of the self-locking valve. A finite element model for the tooling and self-locking valve was established， the correctness of which was verified through modal tests. Based on the modal superposition theory， the shock response characteristics of the self-locking valve were studied， and the locking state of valve spool was judged according to the shock response results and the energy analysis of valve spool. In order to verify the accuracy of the analysis results， a pendulum impact platform was used to carry out impact tests. The locking state of the valve spool obtained was in good agreement with the theoretical results， indicating the effectiveness of the analysis method. The research in this article can provide theoretical foundation and technical support for the anti-shock design of electromagnetic self-locking valves.