Abstract: To address the issues of residue blockage, high seed impurity rates, and high loss rates in the cleaning system of rapeseed pickup harvesters operating in hilly and mountainous terrains, this study designed a dual-airduct cleaning device. The system consists of a scraper conveyor, an acceleration roller, a positive pressure fan, a cyclone separation cylinder, and a negative pressure fan. To prevent blockages in the cleaning chamber and accelerate residue removal, the acceleration roller was designed with a length of 180 mm, a diameter of 100 mm, a spiral blade angle of 25°, and four blades. Based on the kinematic and dynamic analysis of the residue during the cleaning process, the main factors affecting the performance of the device were identified as the acceleration roller speed, the airflow direction angle of the positive pressure fan, and the speed of the positive pressure fan. To validate the performance of the dual-airduct cleaning device, Fluent-EDEM gas-solid coupling simulations were conducted for the rapeseed residue cleaning process. The simulation was set with an acceleration roller speed of 1100 r/min, a positive pressure fan speed of 1600 r/min, and a positive pressure fan airflow direction angle of 20°. During the cleaning process, residues moved in the direction of the airflow, with uniform relative movement trajectories and minimal impact of the residues on the airflow. The airflow had a greater impact on the residue motion. The motion trajectories of different residue components showed that the velocity of the residues underwent two significant changes: the first due to the acceleration roller's action, and the second due to the positive pressure fan airflow. The simulation results indicated that the velocity change of different residue components varied significantly, allowing for better separation of seeds, stems, and impurities, achieving effective cleaning. After the simulation, statistical analysis revealed a seed impurity rate of 2.29% and a loss rate of 2.71%, indicating that the dual-airduct cleaning device was capable of completing the cleaning of rapeseed seeds with a reasonable overall structural design. Using the acceleration roller speed, positive pressure fan airflow direction angle, and positive-pressure fan speed as influencing factors, with seed impurity rate and loss rate as evaluation indices, bench tests were carried out with a feeding rate of 0.2 kg/s. Single-factor tests were conducted within the following ranges: acceleration roller speed (800-1200 r/min), positive pressure fan airflow direction angle (5°-25°), and positive pressure fan speed (1200-2000 r/min). The optimal parameter ranges were found to be: acceleration roller speed (1000-1200 r/min), airflow direction angle (15°-25°), and fan speed (1400-1800 r/min). Based on the single-factor test results, a three-factor, three-level orthogonal experiment was performed. SPSS software was used for range and variance analysis of the test results, which showed that the positive pressure fan speed had an extremely significant effect on both impurity and loss rates. The acceleration roller speed had a significant effect on the impurity rate and an extremely significant effect on the loss rate. The airflow direction angle had a significant effect on both performance metrics. To comprehensively evaluate the impact of each experimental factor on the seed impurity and loss rates, a weighted comprehensive evaluation method was used. Since, in actual cleaning operations, loss reduction is prioritized while keeping the seed impurity rate low, the impurity rate weight was set at 0.4 and the loss rate weight at 0.6. A comprehensive score was used as the evaluation standard. The analysis showed that the main influencing factors on cleaning performance were: positive pressure fan speed, acceleration roller speed, and airflow direction angle. The optimal parameter combination was found to be: acceleration roller speed of 1100 r/min, airflow direction angle of 20°, and positive pressure fan speed of 1400 r/min. Under these settings, the dual-airduct cleaning device achieved a seed impurity rate of 2.35% and a loss rate of 2.75%. Field trials with these optimized parameters showed smooth material feeding with no blockage in the pickup header. The average impurity rate was 3.05%, and the average loss rate was 3.47%. The test results confirmed that both rates were below 5%, outperforming single-airduct cleaning systems and meeting the segmented rapeseed harvesting standards. This study provides theoretical support for the improvement and optimization of cleaning devices in the mechanized rapeseed harvesting process in hilly and mountainous areas.