Pipeline joint air leakage detection device

The invention relates to a pipeline joint air leakage detection device, and aims at effectively solving the problem that existing pipeline joints are lack of online detection devices. The pipeline joint air leakage detection device comprises a circular pipe; a first piston cavity is formed in the side wall of the circular pipe; a first piston is mounted in the first piston cavity; a first air ventand an elastic block are arranged on the side wall of the first piston cavity; a second piston cavity is formed in the lower surface of the first piston; a second piston is mounted in the second piston cavity; a horizontal hole and a vertical hole communicated with the horizontal hole are formed in the first piston; the inner end of the horizontal hole is communicated with the upper end of the second piston cavity; a first plunger is fixed at the top of the first piston cavity; the lower end of the first plunger is penetrated in the vertical hole; an exhaust duct is formed in the first piston; a second plunger is fix