The application discloses circuit breaker attribute testing extension line, circuit breaker and electric power system, wherein, the extension line includes link, transfer unit and test terminal, the link is connected with four stitchs on the control cable, four stitchs respectively with the combined floodgate control coil, the separating brake control coil, combined floodgate lock -up control coil and spring stored energy control coil one -to -one, the link is drawn forth through transfer unit and is connected with the test terminal, the stitch that four of test terminal wiring ends correspond with the combined floodgate control coil respectively, the stitch that the separating brake control coil corresponds, stitch and the corresponding stitch one -to -one of spring stored energy control coil that combined floodgate lock -up control coil pair was answered, and four wiring ends have mark information, so that characteristic testing personnel four the coil types that should connect of wiring terminal pair respectively, thereby very big improvement the efficiency of attribute testing. Need not demolish the circuit breaker front panel and utilize circuit breaker attribute testing extension line to carry out the attribute testing, therefore not have therefore damage the possibility of circuit breaker.