The invention discloses a grain processing and deroughening machine. The machine comprises a base, a deroughening sieve and a deroughening device, two supporting plates are symmetrically fixed at thetop of the base, sliding assemblies are symmetrically fixed on the inner sides of the two supporting plates, the sliding assemblies comprises fixing blocks, sliding rods and sleeves; the two ends of the sliding rods are fixed with the supporting plates through the fixing blocks; the sleeves are connected to the outer side of the sliding rods in a sliding mode, the two sides of the deroughening sieve are respectively fixed with the sleeves, the deroughening device is fixed on the supporting plate on one side of the top of the base, the deroughening device comprises mounting plates, a driving assembly, a rotating disc, a driving shaft, a connecting rod and a transmission gear, the mounting plates are fixed at the top of the supporting plates, the driving assembly is fixed on the mounting plate, the output end of the driving assembly is fixed with the turntable, the driving shaft is fixed on one side, far away from the driving assembly, of the rotating disc. According to the grain processing and deroughening machine, the deroughening sieve can be driven to move in a reciprocating mode through the deroughening device, so that the screening speed of the deroughening sieve is increased,and the deroughening quality of the grain is higher.