A circuit breaker comprising a superconducting fault current limiter and a circuit breaker module, wherein the superconducting fault current limiter and the circuit breaker module are connected in series. The circuit breaker module includes a disconnector, a first semiconductor switch unit, and a second semiconductor switch unit, wherein the disconnector is connected in series with the first semiconductor switch unit, and also connected in series with the superconducting fault current limiter, and the second semiconductor switch unit is connected in parallel with the disconnector and first semiconductor switch unit that are connected in series. The circuit breaker can quickly and securely interrupt a circuit when an overcurrent fault occurs on the circuit.