To meet the requirements of maize grain harvester for cleaning large feeding mass of maize mixture, the double-layer jitter plates with holes were designed to shunt the maize mixture when they entered the cleaning device. The movement of particles after leaving jitter plates before arriving at vibrating screen was analyzed. The position of the upper and lower jitter plates relative to the vibrating screen, the distribution and size of the sieve holes on the upper jitter plate were determined. The angles of the jitter plates installed, the amplitude and the frequency of the jitter plates were chosen as the experimental factors. The time of cleaning maize mixture by the screeens, the cleaning rate and the loss rate of the maize grains were chosen as the performance indexes. The CFD-DEM coupled method was used. The effect of test factors on performance indexes was determined. The quadratic orthogonal rotational-combinational simulation tests were designed. The regression mathematical models between factors and indexes were founded. When the inlet velocity of airflow was 12.8m/s, the direction angle of airflow was 25°, the feeding mass was 7kg/s, the best combination of parameters were that the angle of the jitter plates installed was -3.85°, that the frequency of the jitter plates was 5.62Hz and the amplitude of jitter plates was 44.77mm. The cleaning and loss rate of maize grain and the time of cleaning maize mixture by the screens were 98.36%, 1.45% and 6.74s, respectively. Compared with the cleaning system with single-layer jitter plate, the cleaning rate of maize grain was reduced by 1.72 percentage points, the loss rate of maize grian was reduced by 0.84 percentage points and the time of cleaning maize mixture was shortened by 0.57s. The performance tests were done in the laboratory to verify the accuracy of the simulation results.