The mechanism of abnormal combustion of hydrogen fueled engines was discussed in this paper for controlling abnormal combustion of hydrogen fueled engines, and providing references to resolve the contradiction between abnormal combustion and power output. Moreover, the relationship between pre-ignition of hydrogen fueled engine and its pressure rise rate was analyzed, and diagnosed method on the pre-ignition was investigated. The experiment results showed that the time and the severe degree of pre-ignition under different pressure rise rate could be diagnosed by using the wavelet analysis method. Based on the experiment it is found that the most important factors effecting pressure rise rate of hydrogen fueled engines are spark advance and excess air ratio. Finally, the formulae between the pressure rise rate of the engine and spark advance, and between the pressure rise rate of the engine and excess air ratio, were respectively established by data fitting, so that control law about the pressure rise rate of the engine was also formed. This can provide a mensurable method for restraining the abnormal combustion of the engine.