Cylinder head and fuel injecting vibration consist of rich information about the working state of the locomotive engine, which shows important potential on the engine fault online diagnosis and regular maintenance. Through acquiring the cylinder head and fuel injecting vibration signals, comparing with the standard signals, fault diagnosis strategy is researched. By analyzing the cylinder head vibration curve with the method of vibration comparison value, the working states of all the cylinders are obtained. With the vibration curve of the fuel injecting, the problem of the injectors is found which helps to locate the fault. The strategy is applied to the No.0015 locomotive of the Rizhao Seaport Transportation Company. The matching between the analysis result and practical locomotive state shows the validity of the strategy which can dramatically improve the maintaining efficiency as well as decrease the degree of over maintenance and lack of maintenance.