To improve the dust collection efficiency of sweepers, the computational fluid dynamics method was applied to simulate the blowing-suction cleaning flow field. Influence of structural parameters on cleaning effect was analyzed combined with the gas-solid two-phase flow model. The multi-objective orthogonal test method based on weight matrix analysis was used to optimize the position parameters. Results show that when the width of the blow mouth was less than 0.93 of the width of the suction mouth, it is beneficial for improving cleaning efficiency with the increase of the width of the blow mouth. When the height of the blow mouth was more than 0.92 of the height of the suction mouth, the cleaning efficiency was improved with the increase of the height of the blow mouth, but the mean velocity near the ground and the outlet velocity of the blow mouth were reduced, which was not conducive to blowing up the dust. When the inclination of the blow mouth was 20°, the inclination of the suction mouth was 20°, the distance between the blow mouth and the suction mouth was 700 mm, and the height from the two mouths to the ground was 20 mm, the cleaning performance of the blowing-suction cleaning method was optimal. The airflow velocity was high near the ground in the blowing-suction cleaning flow field, where the airflow moved from the blow mouth to the suction mouth and the direction was close to the ground. There was no secondary pollution caused by the leakage of the airflow. The inclination of the blow mouth and the inclination of the suction mouth had the greatest influence on the cleaning performance, followed by the distance between the blow mouth and the suction mouth, and the height from the two mouths to the ground had the least effect.