A simple peak junction working temperature predicting model on the pulse width modulation working condition was established in order to accurately estimate the temperature rise of power MOSFET within engine controller. The model can make an accurate prediction of the peak junction temperature under pulse width modulation operation based on the components DATASHEET parameter. The measured temperature-rise results with experiments were provided to verify the model prediction accuracy. The prediction results match the experiment results very well and the maximum error is less than 2.3%. Although temperature prediction is based on the solenoid valve drive circuit, the analysis results can be easily extended to other power device drive circuitry topology.