Electronic components vibration fault in control box of diesel generator was analyzed by experimental test and numerical simulation. Experimental results show out that the key point vibration amplitude of control box is small when the diesel generator works on its normal rotational speed, there isn’t overload. So the strong vibration which induced fault may happen during diesel generator starting or shutdown. Then finite element model of vibration was established by Ansys to calculate model shape of frequency range in 0~50Hz. Studies show that several modal shape frequencies are in the range of 0~50 Hz, three sympathetic vibration of control box happened and displacements are larger then experimental test. Corresponding accelerations are also much larger then gravity acceleration, maybe induce serious overload. So connecting pins of electronic components may be tore by the overload force. After analyzing, it can be concluded that the anti-overload ability of electronic components must be taken into account.