The invention discloses a piston air-assisting double-energy type high-pressure SF6 (Sulfur Hexafluoride) circuit breaker arc extinguishing chamber, and belongs to the technical field of high-pressureSF6 circuit breakers. The arc extinguishing chamber is characterized in that a fixed contact mechanism (4), an inner base (14) and a moving contact mechanism are fixed in an arc extinguishing chambershell (7); the moving contact mechanism is independently spaced from the fixed contact mechanism (4) and the inner base (14) to form a thermal expansion chamber (21) and an air compression chamber (16); and two air chambers are communicated through an air duct (12). In the piston air-assisting double-energy type high-pressure SF6 circuit breaker arc extinguishing chamber, a movable clapboard is arranged, during closing, the movable clapboard enables the volume of the thermal expansion chamber to be reduced, so that airflow still flows between the moving contact mechanism and the fixed contactmechanism, and the possibility of closing arc discharge is avoided and reduced. The designed air compression chamber is cooperated with the thermal expansion airflow of the thermal expansion chamber,mechanical energy and thermal energy are fully combined to carry out opening arc discharge, the possibility of the opening arc discharge is effectively reduced, in addition, arc quenching speed is high, and arc quenching reliability is high.