The air-lift device has the advantages of simple structure and low operating cost, and is widely used in the field of water treatment. In this paper, a theoretical model of the air-lift system is established, and the effects of the intake airflow, the diameter of the lifting riser, the submergence rate, and the cross-sectional surface area of the suction port on the suction flow rate and the suction efficiency of the sewage suction device at the bottom of the pipeline air-lift tank are respectively investigated. Through experiments, the influence law of intake flow, riser pipe diameter, submerged rate, and suction cross-sectional area on the suction flow rate and suction efficiency of the sewage suction device was studied. The experiment shows that the flow velocity and suction efficiency of the suction port has a linear relationship with the intake flow and the submergence rate; under the condition of constant pipe diameter, the flow velocity of the suction mouth decreases with the increase of the cross-sectional area of the suction mouth, and the suction efficiency tends to be stable after the increase of the suction efficiency. Under the working conditions of the intake flow rate of 6m³/h, submersion rate of 0.778, lift riser pipe diameter of 50mm, and suction cross-sectional surface area of 226mm2, the pipeline-type pneumatic lift pool bottom sewage suction device can achieve optimal performance. This research also provides theoretical guidance for the follow-up equipment research and development, testing and promotion, and application.