Abstract: Abstract: The qualified rate and the entrainment rate was caused by the unreasonable working parameters of the key working parameters of the belt separator for peanut seeds, in order to make them to be a reasonable level, the central composite experiments were conducted to optimize the working parameters. Firstly, the physical properties of peanut seeds were studied, and the study object was "Huayu 33" planted widely in Shandong province. The shape of "Huayu 33" peanut seeds was oval, the thousand seeds weight of which was 812.10 g, the length, width and thickness were mainly at 16.23-19.17, 8.07-10.37, 7.17-8.36 mm, respectively. The moisture content of peanut seeds was 9.3%. The rolling friction angle of high quality peanut seeds was 14.3°, and the angle of static friction angle of crushed half seeds was 35.7°, which were tested by inclined surface device. The effects of key working parameters of peanut seed belt separator, including longitudinal angle, heeling angle, velocity of canvas belt on qualified rate and entrainment rate, were analyzed. And then the composite experiment methods of quadratic orthogonal rotation were adopted, the data were analyzed based on the design-expert software, the mathematical regression models of qualified rate and entrainment rate were built, and their corresponding variance analysis were conducted too. A regression equation of the relationship between variation coefficient of the 3 key working parameters was obtained. Analysis of variance showed that the velocity of canvas belt was the biggest factor that affects the qualified rate and entrainment rate, and the smallest impact factor was the distance between rotary and stationary plate; regarding to the breakage rate, the biggest factor was working face width of stationary plate, and the smallest factor was heeling angle. The response surface method was utilized to analyze the effects of factors' interaction on qualified rate and entrainment rate, and the multi-objective optimizations were conducted for the regression models to obtain the working parameters of high qualified rate and low entrainment rate. The optimal combination working parameters of peanut seed belt separator were as follows: velocity of canvas belt was 0.7 m/s, longitudinal angle was 23.22(, and heeling angle was 25.21(. All of those were obtained by the optimization solution of all factors with the quadratic regression model equation of performance evaluation indices in the range of experimental parameters constraints. Under the condition of the optimal combination working parameters, the qualified rate and the entrainment rate were 97.20% and 2.73%, respectively, which met the premium grade of belt separator according national standard and the need of peanut seeds processing industry. The results of verification test were highly consistent with the results of optimization solution. The production verification test was conducted on the peanut seed production line in the factory, the working parameters of belt separator were adjusted according to the optimization results in the test. Through optimizing the parameters of the belt separator, the qualified rate was greatly improved, and the qualified rate and entrainment rate were 95.8% and 3.9% respectively, which were very close to the previous simulation results. The results of optimization are helpful for the improvement of belt separator for peanut seeds.