Based on semiconductor physics and the essential structure of insulated gate bipolar transistor (IGBT), the model of dV_CE/\d t is established through reasonable simplification and theoretical derivation. The influencing factors and temperature characteristics of dV_CE/\d t are studied in depth. It is concluded that dV_CE/\d t increases linearity with the increase of voltage or current, and decreases with the increase of junction temperature also linearly. On the basis of the model for dV_CE/\d t, the prediction model of junction temperature is established. Results of simulations and experiments verify the correctness and accuracy of the models. It is significant in theory and practical application for realizing IGBT junction temperature monitoring on-line and improving the reliability of IGBT module and power electronic equipment.