The utility model belongs to the technical field of a technique of high voltage electric power equip ment and specifically relates to a single -phase operation knob insulator formula circuit breaker of 145kV, including component parts such as explosion chamber, mechanism's case, transmission case, insulating pull rod, interior turning arm, outer turning arm, support, girt and CT26 mechanisms. The explosion chamber of circuit breaker passes through the bolt fastening and on the support, is provided with interior turning arm in the transmission case among the transmission, and interior turning arm one end is connected with the insulating pull rod of explosion chamber, and the other end passes through the outer turning arm in integral key shaft and the transmission case outside to be connected, and outer turning arm passes through girt and CT26 mechanism and articulates and be connected, and wherein the incasement in the mechanism is placed by CT26 mechanism. Three operating mechanisms all be connected with electric interlocking. The utility model discloses each all has mutually one set of transmission, operating mechanism the circuit breaker, realizes the single -phase closing operation that independently divides of circuit breaker, has rational in infrastructurely, and transmission efficiency is high, stable performance, advantage such as simple reliable.