Outdoor high-voltage alternating-current porcelain knob type SF6 circuit breaker

The utility model discloses an outdoor high-voltage alternating-current porcelain knob type SF6 circuit breaker, which comprises a frame, three porcelain knobs and arc extinguishing chambers. The three porcelain knobs are arranged on the frame, each porcelain knob is provided with one arc extinguishing chamber; and each arc extinguishing chamber comprises a porcelain bushing, a fixed terminal on the upper portion of a cavity of the porcelain cavity and a movable terminal on the lower portion of the cavity. As the structure of a contact of the circuit breaker is modified, the inner diameter of a movable arc contact structure is reduced, flowing of air around the contact is not affected during the on and off process, and on and off of the circuit breaker are also not affected.