Abstract: To improve the sifting efficiency of plansifter on different materials in flour milling systems and improve milling quality and efficiency, sieving tests were conducted on milled materials from the break system, reduction system, sizing system, and tailing roll in a typical flour milling production line. The differences in sieving effects of materials with distinct characteristics under different motion parameters were analyzed and studied. The results showed that the centrifugal acceleration of flat sieving motion had a significant impact on the sieving effect. For separating coarse semolina from materials in the front break system and sizing system, the optimal sieving effect was achieved when the centrifugal acceleration (ω²r) was 9.37 m/s², with motion parameters of a rotating diameter (D) of 65 mm and a rotational speed (n) of 162 r/min. The optimum screening effect was achieved at ω²r=10.96 m/s² for the grind of the back-road break system with motion parameters of D=65 mm and n=175 r/min. For materials in the reduction system, when using 11XX sieves, the material of the front reduction system achieved the best sieving effect at ω²r=18.51 m/s², with motion parameters of D=50 mm and n=260 r/min. For materials in the back reduction system and tailing roll system sieved with 12XX sieves, the most ideal sieving effect was observed at ω²r=20.71 m/s², with motion parameters of D=50 mm and n=275 r/min. Therefore, in actual production, the motion parameters of flat sieves should be optimally selected based on the system position, particle size characteristics, and sieving requirements of materials to improve sieving efficiency.