The invention discloses a novel three-phase integrated isolated circuit breaker integrated all-fiber optical current transformer. Circuit breaker arc extinguish chambers are connected with optical fiber composite sleeves through transition flanges and conductive support flanges; a circular through hole is formed in the center of each conductive support flange; the conductive support flanges are step-shaped; annular grooves are formed in steps with relatively large cross sections; all-fiber optical current transformer sensitive loops are positioned inside the annular grooves; the all-fiber optical current transformer sensitive loops are connected with an all-fiber optical current transformer electric unit through the optical fiber composite sleeves; end surfaces, without the annular grooves, of the conductive support flanges, are fixedly connected with the optical fiber composite sleeves; end surfaces, with the annular grooves, of the conductive support flanges, are fixedly connected with the transition flanges; the transition flanges are fixedly connected with the circuit breaker arc extinguish chambers; insulating paint is sprayed between the transition flanges and the conductive support flanges; wiring terminal plates are fixedly connected with the end surfaces, without the annular grooves, of the conductive support flanges. The novel three-phase integrated isolated circuit breaker integrated all-fiber optical current transformer is small in floor space, good in grid stability, high in mounting integration and low in cost.