Bidirectional feed pneumatic separating system

A bidirectional feed pneumatic separating system comprises a stem and shred separating machine (2), high-speed belt conveyors (1 and 1.1), pneumatic doors (11 and 11.1), a discharge port (6), an impurity discharge hopper (5) and a wind speed adjusting plate (21), wherein the high-speed belt conveyors (1 and 1.1) are installed on the left side and the right side of a winnowing chamber (16), material throwing openings of the high-speed belt conveyors are sealed through cover plates (8), the pneumatic doors (11 and 11.1) are installed on the two sides of the stem and shred separating machine (2) and slide and run up and down in slide ways, the discharge port (6) is installed above the winnowing chamber (16), the impurity discharge hopper (5) is arranged below the winnowing chamber (16), the discharge port (6) is provided with an adjusting valve (19), the discharge hopper (5) is designed through a mesh plate, and the wind speed adjusting plate (21) is installed in the winnowing chamber (16). By means of the bidirectional feed pneumatic separating system, a vibrating conveying system of an existing stem and shred separating machine is omitted, a material throwing system of the stem and shred separating machine is omitted, material smashing is reduced, and the material shred integrity rate is increased. Feed can be conducted on the two sides of the stem and shred separating machine independently, multiple purposes can be achieved through one machine, and the process requirements of a user are met.