The invention discloses an explosion-proof positive pressure biological fermentation tank, comprising a tank body, a support leg is fixedly connected to the bottom of the tank body, a motor support rod is fixedly connected to one side of the support leg, and the motor support rod is One end is fixedly connected with a motor, the output shaft of the motor is fixedly connected with a rotating shaft through a coupling, one end of the rotating shaft penetrates and extends into the interior of the tank, the surface of the rotating shaft is fixedly connected with a bearing, and the surface of the rotating shaft is fixedly connected with a blade, the tank The surface of the body is provided with a feed port, one end of the feed port is screwed with a feed port sealing plug, and the surface of the tank body is provided with a discharge port. In the explosion-proof positive pressure biological fermentation tank, the surface of the adjustment block is convex. When the internal pressure of the tank is too large, the pressure will push the adjustment block on the inner wall of the adjustment port, and the resulting gap is conducive to the release of the pressure in the tank, so as to solve the problem. The problem of damage to the fermenter caused by the air pressure generated during fermentation in the fermenter is solved.