A self-propelled potato collecting and bagging machine was designed to address the issues of high labor intensity, low efficiency, and high cost in manual picking during potato segmented harvesting. The self-propelled potato collecting and bagging machine can complete the tasks of potato picking, potato soil separation, seedling removal, and bagging in one go. Elaborating on the overall structure of the self-propelled potato collecting and bagging machine, a detailed design of key components such as the picking device, lifting chain device, thrid conveyor chain device, sorting table, and unloading device was provided; the DEM-MBD coupling method was used to analyze the movement process and force situation of potatoes at the intersection of two conveying chains; the Box-Behnken test method was used to carry out four factors and three levels experimental research on the working parameters of the machine, with the potato leakage rate and the potato damage rate as the evaluation indicators, and the forward speed of the machine, the linear speed of the picking device conveyor chain, the lifting chain, and the third conveyor chain as the test factors. The quadratic polynomial regression model was established by using Design-Expert software. After optimizing the regression model, response surfaces were drawn and the optimal operating parameters of the machine were obtained. Finally, field experiments showed that when the forward speed of the machine was 0.70m/s, the conveying chain speed of the picking device was 1.10m/s, the lifting chain speed was 1.20m/s, and the third conveying chain speed was 1.30m/s, the potato leakage rate was 2.82% and the potato damage rate was 3.61%, which met the requirements of potato collecting operations.