The invention provides a feedstock stirring device for a methane tank and belongs to the technical field of agricultural equipment. The problem that raw materials of existing methane tanks are not uniformly stirred before fermentation is solved. The feedstock stirring device for the methane tank comprises a cylindrical mixing drum which is horizontally arranged above the methane tank. The top of the mixing drum is provided with a feed inlet; the bottom of the mixing drum is provided with a discharge port; and the bottom of the mixing drum is connected to a discharging plate. The discharging plate covers below the discharge port. A rotary plate is arranged inside the inner chamber of the mixing drum. Several stirring shafts, which are arranged in a ring array with the center line of the mixing drum as the center, are rotatably connected onto the rotary plate. Strip-shaped stirring plates, which can be always horizontally arranged, are fixedly connected onto the stirring shafts. The mixing drum is provided with a driving structure used for driving the rotary plate to rotate. By the device of the invention, efficient stirring and uniform mixing of raw materials can be realized, and raw materials also can be avoided from being turned out of the feed inlet at the top of the mixing drum.