With the development of HVDC and DC grid technology, it is becoming more and more urgent to study DC Circuit Breakers (DCCB) with the high reliability and economy. However, the simulation results are not accurate enough in the current studies on DCCB topologies which ignore the transient electrical characteristics (TEC) of IGBT during the switching process due to the IGBT ideal switching models. This paper firstly studies the interruption process of hybrid DC circuit breaker based on cascaded diode-bridged sub-module (SM), and a theoretical analysis about the TEC of the interruption process of DCCB is made. The IGBT composite model and ideal model are compared and fault breaking simulation platform of DCCB is built then. Finally, the simulation and comparison of DCCBs based on IGBT composite model and ideal model are carried out, respectively. It can be shown that the IGBT composite model can reflect the breaking characteristics of device in microsecond scale and help to get more accurate TEC than ideal model. The application of IGBT composite model is helpful to learn the TEC of DCCB deeply.