The invention discloses a device for testing on-off performance of a direct current breaker, and relates to the technical field of direct current breaker on-off performance testing. The device is provided with an upper supervisor, and the upper supervisor is in communicating connection with a direct current breaker on-off performance testing module through RS485. The direct current breaker on-off performance testing module is composed of a data collecting unit, a controlling and adjusting unit and a test power module. The data collecting unit comprises a shunt, a storage recorder, a microprocessor, a keyboard and a display device. The controlling and adjusting unit comprises a remote control relay, a time relay, a scram button, a direct current contactor, parallel resistors R1...Rn, IGBT tubes K1...Kn and an optocoupler. The test power module comprises an AC/DC rectifying module and a super capacitor. The device has the advantages that 1-1000A large constant currents can be provided, the tripping time of the breaker under different short-circuit currents can be tested, the potential hazards that in a direct current system, the dispersion and the internal resistance of the direct current system breaker are inconsistent, and stage difference coordination is not reasonable can be timely found, and operation resistance and misoperation possibly existing in the direct current breaker are effectively avoided.