Abstract: Aiming at the fault protection and power flow control problems of the multi-terminal flexible DC grid, this paper proposed a multi-port hybrid DC circuit breaker with power flow control function. The proposed breaker consists of two parts: the through-flow branch and the main breaker branch. When the system is in the steady state operation, it has a power flow control function, which can adjust the branch power flow; when the system fails, the structure is equivalent to a hybrid DC circuit breaker for cutting off the fault current. A multi-port hybrid DC circuit breaker topology with power flow control function was established; the steady-state and transient operation mechanism were elaborated; and the economic characteristicswere analyzed. Finally, a four-terminal DC transmission system was built on the PSCAD simulation platform to verify the proposed topology, which has good performance in power flow control and fault removal.