For power electronics devices, the junction temperature that can be measured by the Temperature Sensitive Electrical Parameter (TSEP) indirectly is a key condition variable. In this paper, the dv/dt of converter output voltage is measured as the TSEP for diode junction temperature, which mainly depends on the reverse recovery characteristic affected by temperature and current. To clarify the method, the measurement system, procedure and principle are presented. Simulation and experiments were implemented to verify the effectiveness and feasibility of the method. Research results demonstrate that the diode junction temperature can be measured accurately during PWM operation from the terminal of power converter with the advantages of simple and cost-effective.