Abstract: The wind speed, air duct, and other factors are crucial for the impurity content and loss rate in the fan cleaning system of chili harvesters.If the wind speed is high, the impurity content is low but the loss rate is high.Anyway, the impurity content is high but the loss rate is small.Therefore, a reasonable design of air ducts and wind speeds is beneficial for improving the operational performance of pepper harvesters.This article uses simulation analysis software to analyze the wind speed and air ducts of the cleaning system, and obtains the optimal layout, providing reference for the overall design of the machine.