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In order to improve the screening performance of the air-screen cleaning device of maize grain harvester, the relationship between the motion of grain on the screen and the function f(x) of screen-shape was determined through the mechanics analysis of particle. In order to propose a type of sinusoidal-shape screen, the woven screen was studied. Computational fluid dynamics and discrete element method (CFD-DEM) were coupled to compare and analyze the airflow in the cleaning device and the characteristics of flat, convex and concave screening. The screening performance of the sinusoidal-shape screen, compared with this one with tail screen was removed, was better. The quadratic orthogonal rotational-combinational simulation tests were designed. The coefficient of screen-shape and the inlet velocity of airflow and the direction angle of airflow were taken as factors, and the loss and cleanliness of maize grains collected were taken as indexes. The regression mathematical models between factors and indexes were multi-objective optimized by using Design-Expert software. The best combination of parameters was obtained, including the coefficient of screen-shape of 32.35mm, the inlet velocity of airflow of 13.73m/s, the direction angle of airflow of 23.86°. The best combination of parameters was set in the bench test. The flat weave screen was compared with that of the screening performance of sinusoidalshape screen. The experimental results showed that the sinusoidalshape screen can realize the fast passage of maize debris, and increase the possibility of maize grains passing the screen when the total feeding quantity was 5kg/s and the vibration frequency of the screen was 5.15Hz. The working mechanism and screening performance of the sinusoidal-shape screen were tested by highspeed camera and indoor bench. The experimental results showed that the state of movement of maize mixture on different screens was more favorable to the performance of the cleaning device. The cleaning rate of maize grains collected was 98.07% and the rate of maize loss was 1.16% after screening. Compared with the flat weave screen, the cleaning rate of maize grains was increased by 2.45 percentage points and the rate of maize loss was reduced by 0.79 percentage points, which met the requirements of technical specification for quality evaluation of screening in China.