The wheat flour is mixing by the dough mixer through adding water, then enters the homogenizer for homogenization, so that the batter mature and protein quickly condensed, so as to separate starch and protein. After homogenization, the flour paste enters the tri-canter, and the light phase, the second heavy phase and the heavy phase are separated. The light phase is the soluble pentosan. The second phase is B starch, gluten and a small amount of fiber. The heavy phase is mainly A starch and fiber. The second phase is sieved by the arc screen, then washed by the rotary screen to get the bottom flow B starch and a small amount fiber as well as the gluten on the screen. The gluten is dehydrated by the squeezer and dried by the gluten dryer, then the qualified gluten product is obtained. The bottom flow passes through the centrifugal sieve to separate the B starch and fiber, and after the separation, separates the mixed small amount of A starch. After the refined B starch is dehydrated and dried, the B starch product is obtained. The A starch and fiber separated by the tri-canter, the fiber separated from B starch and the A starch separated from the B starch are mixed, and the fiber is separated by the centrifugal sieve, and then the starch milk enters the separator for the further separation. The separated A starch goes through the refinery, dewatering and drying, then get the qualified A starch.