Metering pump consists of motor, drive end and hydraulic end. The electric motor drives the eccentric mechanism to rotate through the worm gear, and the eccentric mechanism drives the diaphragm through the push rod. The regulating mechanism realizes the flow control by adjusting the eccentric distance. Diaphragm reciprocates with preset stroke length. The diaphragm is pulled back to allow the medium to flow into the chamber through the check valve. The diaphragm is pushed forward so that the same amount of medium is discharged from the outlet check valve. Continuous suction and discharge to achieve precise transfer of medium.