The invention discloses a discharge valve for a positive pressure dense phase pneumatic conveying system. The discharge valve for the positive pressure dense phase pneumatic conveying system comprisesa pipe body which is rotationally provided with a rotating shaft, a turnover piece is arranged at the bottom of the rotating shaft, a transverse rod is fixedly connected to the top of the rotating shaft, and a reset spring is connected between the transverse rod and the pipe body. An inserting connection rod is arranged at one end of the transverse rod, a support is further arranged on the pipe body, a fixing seat is arranged on the support, a pull rod is arranged in the fixing seat in a pulling mode, and the pull rod is movably connected with the other end of the transverse rod. According tothe discharge valve for the positive pressure dense phase pneumatic conveying system, the body is provided with the rotating shaft, the rotating shaft rotates to drive the turnover piece to control the discharge quantity, the inserting connection rod is arranged on the rotating shaft and used for being connected with an external power arm, the rotating shaft is further movably connected with a lever, and the lever is used for being connected with an external control rod, so that opening and closing of the valve can be achieved through a mechanical device without manual operation, and the automation degree is higher.