The present invention provides a hybrid DC circuit breaker, wherein the hybrid DC circuit breaker comprises: a mechanical switch connected in a first current branch; and a semiconductor switch and a forced resonant injection circuit connected in a second current branch, wherein the forced resonant injection circuit comprises a first terminal and a second terminal, the first terminal of the forced resonant injection circuit is connected to one end of the semiconductor switch, and the second terminal of the forced resonant injection circuit and the other end of the semiconductor switch are connected to two ends of the mechanical switch; wherein, when the mechanical switch is in a process of switching off, the semiconductor switch is controlled to be switched on, and at the same time the forced resonant injection circuit is controlled to inject to the mechanical switch a gradually increasing injection current in a direction opposite to that of a current in the mechanical switch, so that the current in the mechanical switch gradually decreases to zero and the current is commutated from the first current branch to the second current branch in a predetermined commutation time. The hybrid DC circuit breaker of the present invention can safely and reliably switch off a fault and load currents in either direction.