A dual-channel injection bipolar high frequency electrosurgical knife, comprising: an electrode part, a main part and an operation part; wherein the electrode part is provided at a distal end of the bipolar high frequency electrosurgical knife, comprising an active electrode configured for cutting tissue and injecting liquid, the active electrode is configured to be extendable or retractable relative to a distal end of the main part, the active electrode has a hollow tubular portion extending in the axial direction and a protrusion provided at a distal end thereof, an insulating part covers an outer surface of the active electrode for isolating the active electrode from an inert electrode, and the insulating part includes a hollow tube and a protruding structure at least on one side, a lumen of the hollow tube is larger than the outer diameter of the hollow tubular portion of active electrode that allows liquid to flow between the active electrode and the insulating part, the inert electrode comprises a hollow tubular structure and a barb structure arranged at a distal end thereof, the barb structure is configured to be able to be engaged with the protruding structure of the insulating part; the main part is provided at a proximal end of the electrode part, including an insulation sheath, the insulation sheath comprises a first channel and a second channel, the first channel restrains the hollow tubular portion of the active electrode, a proximal end of the hollow tubular portion of the active electrode connects with an insulation coated screw by a connector, thereby providing a first liquid passageway, a seal covers the outer surface of the connector and the insulation coated screw, an outer diameter of the seal is smaller than a lumen of the first channel, thereby forming a second liquid passageway in the first channel, the second channel restrains a wire that passes through the insulation sheath which is constituting the second channel, the wire being connected to an inert electrode which is covering the distal outer surface of the insulation sheath; the operation part is provided at the proximal end of the main part, including a connection cable which is connected with the active electrode through the insulation coated screw and with the inert electrode through the wire, and liquid inlets configured to make the liquid separately flow to the first liquid passageway and the second liquid passageway. an electrode part, a main part and an operation part; wherein the electrode part is provided at a distal end of the bipolar high frequency electrosurgical knife, comprising an active electrode configured for cutting tissue and injecting liquid, the active electrode is configured to be extendable or retractable relative to a distal end of the main part, the active electrode has a hollow tubular portion extending in the axial direction and a protrusion provided at a distal end thereof, an insulating part covers an outer surface of the active electrode for isolating the active electrode from an inert electrode, and the insulating part includes a hollow tube and a protruding structure at least on one side, a lumen of the hollow tube is larger than the outer diameter of the hollow tubular portion of active electrode that allows liquid to flow between the active electrode and the insulating part, the inert electrode comprises a hollow tubular structure and a barb structure arranged at a distal end thereof, the barb structure is configured to be able to be engaged with the protruding structure of the insulating part; the main part is provided at a proximal end of the electrode part, including an insulation sheath, the insulation sheath comprises a first channel and a second channel, the first channel restrains the hollow tubular portion of the active electrode, a proximal end of the hollow tubular portion of the active electrode connects with an insulation coated screw by a connector, thereby providing a first liquid passageway, a seal covers the outer surface of the connector and the insulation coated screw, an outer diameter of the seal is smaller than a lumen of the first channel, thereby forming a second liquid passageway in the first channel, the second channel restrains a wire that passes through the insulation sheath which is constituting the second channel, the wire being connected to an inert electrode which is covering the distal outer surface of the insulation sheath; the operation part is provided at the proximal end of the main part, including a connection cable which is connected with the active electrode through the insulation coated screw and with the inert electrode through the wire, and liquid inlets configured to make the liquid separately flow to the first liquid passageway and the second liquid passageway.