Abstract: The malfunction and failure of an aerospace phased array antenna during the random vibration test are studied in this paper. First, the root causes are identified by fault tree and assessment experiments. It is found that the main cause of the DSP chip crack is stress concentration on pins during vibration. Then, the acceleration and stress responses of DSP chips under the test conditions are calculated by finite element simulation. The simulation results are well consistent with the experimental results. Finally, the main structure of phased array antenna is optimized based on the finite element model by increasing the stiffness of the main structure, optimizing the DSP chip layout and adding the rubber absorber between the wave controller module and the main structure. The simulation results show that the dynamic response of the DSP is greatly improved after optimization, which is verified by vibration test. This study provides theoretical and experimental basis for the vibration damping design of high order random vibration.