The invention discloses a stop valve for an air conditioner. The stop valve comprises a valve body (1) with a valve cavity (11), an inlet connection pipe (3) which is fixedly connected with the valve body (1) and an outlet connection pipe (4) which is movably connected with the valve body (1), and the stop valve is characterized by also comprising a connection device of the outlet connection pipe (4), the connection device comprises an elastic fixed clamping ring (6), a sealing part (82) and a compression part (7); the elastic fixed clamping ring (6) comprises a compression end part (61) and a conical guide part (62), and the compression end part (61) is provided with a plurality of openings (63) which are symmetric about the axis and stretch into the conical guide part (62) along the axial direction; and the conical guide part (62) is provided with a plurality of openings (64) which are symmetric about the axis and stretch into the compression end part (61) along the axial direction, and the openings (63) and the openings (64) are arranged at intervals along the circumferential direction. By adopting the stop valve, the internal leakage problem caused by the deformation of the valve body due to the compression torque can be avoided, the leakage potential danger caused by the deviation of the matching of the connection parts can be prevented, and unfavorable products can be reduced.