Designs a new type of air-lift pump (gas-injection pump). With riversand (diameter 1~3 mm) as the work object, makes an experimental study on gas-injection pump from lifting water capacity, lifting solid particles capacity and efficiency of lifting solid particles. The experiment shows that gas-injection pump can lift solid particles effectively and the main factors affecting the capacity are the submergence ratio and the flow rate of air supplied: there exists an optimal value of air supply which makes the flow rate of solid particles biggest and the more the submergence ratio, the stronger lifting solid particles capacity.