Efficient fine-screening automatic classifier

The utility model belongs to the technical field of grain separating machines, and discloses an efficient fine-screening automatic grain separating machine which comprises a box body, a box door is installed on one side of the box body, a feeding hopper is fixed to the top end of the box body, three fixing frames are installed in the box body, screen meshes are connected to the interiors of the three fixing frames, and the screen meshes are fixed to the top end of the box body. A vibrating motor is installed on the bottom side of the fixing frame, a material collecting frame is connected to the position, close to the lower portion of the screen, of the bottom end of the interior of the box body, a collecting box is fixed to one side of the box body, a conveying pipe is installed at the top end of the collecting box, and a branch pipe is fixed to the position, close to the upper portion of the screen, of the side wall of the box body; through the cooperation of the conveying pipe, the branch pipe, the exhaust