During use of an air flow meter, the flow of gas through the flow meter drives the turbine blades to rotate. The number of revolutions of the impeller is proportional to the volume of gas passing through the air flow meter. A specially designed patented deflector is installed at the inlet of the flowmeter, which accelerates the airflow entering the flowmeter as the flow rate increases. The deflector is designed to eliminate any potential fluid disturbances such as vortices or asymmetrical flow. The thrust on the turbine blades also increases at the same time. It ensures that the flowmeter measures with high precision within the allowable error range, and can measure accurately even in the condition of small flow. The airflow acting on the turbine blades is axial, and the turbine is mounted on the main drive shaft, which is equipped with high-strength ball bearings. After the gas passes through the turbine blades, the rotation of the turbine blades is decelerated by the gear set. The pressure in the inlet channel of the air flow meter is restored, and the channel design ensures the optimization of the flow regime.