With MMC-HVDC technology gradually expanding to overhead line transmission occasions, the rapid identification and isolation of fault lines is particularly important. Compared with the cable line, the overhead line transmission is prone to happening short circuit, flashover and other transient faults, and corresponding measures must be taken to isolate the fault line to avoid system outage immediately. DC circuit breaker has captured great attention from the community at home and abroad as the core equipment of isolating fault circuit. A new type of hybrid DC circuit breaker topology is proposed based on the existing DC circuit breaker technical scheme. The circuit breaker can effectively restrain the amplitude of short circuit current through the current limiting inductance, and avoid the synchronous driving and voltage sharing of large orders of IGBT series by means of capacitive buffer action. A model of four-terminal double bipolar HVDC grid is built on the PSCAD/EMTDC, and the simulation results show that the DC circuit breaker can meet the demand of fast resection of the fault line. This work is supported by Science and Technology of State Grid Corporation of China (No. JBB17201600241) “Study on AC Power Grid Protection Influenced by ±500 kV Flexible DC Power Grid”.