Abstract: Aiming at the problems of fewer peanut seed grading treatment tools and easy clogging of sieve holes before sowing, a flexible belt peanut seed grading device is designed, which uses seeds to be graded from different gaps with the movement of adjacent grading belts. The physical characteristics of Yuhua 22 peanut seeds, a typical variety in the main production area of Henan Province, were measured, and the key parameters such as the layout and inclination angle of the grading zone were determined. The experiment was designed by quadrature orthogonal rotary combined experiment method, and the data processing of the experimental results was carried out by Design-Expert, and a regression mathematical model and analysis of variance with hierarchical accuracy were established. Through ANOVA, the primary and secondary factors affecting the grading device are: grading band speed, inclination angle, and grading band diameter. By analyzing the influence of the interaction of various factors on the grading accuracy by the grading accuracy by the response surface method, the optimal combination of key operating parameters is obtained as follows: grading band speed 0.32 m/s, inclination angle 4.5°, grading band diameter 8.09 mm, and grading accuracy of 97.27% under this condition. The optimization parameters are further verified, and the grading accuracy is 95.84%, and the grading performance is better, which can meet the needs of small batch peanut seed grading.