The flow is based on the principles of differential pressure flow meters, pulsating flow absorption method, Boyle's law, and Poisson's law; Install throttle orifice plates, differential pressure gauges, and sealed energy storage filtering containers on the main pipeline for drug delivery; The output signal of the differential pressure gauge is processed by a microprocessor for data processing such as square root, filtering, slope correction, and curve translation, and the measured value is displayed on the screen; At the same time, the signal is compared with the given value, and after PID adjustment, the output signal controls the number of times the electromagnetic valves at dozens of dosing points are opened per unit time, thereby controlling the amount of medication added. The dosage measurement and control device composed of the above links has achieved accurate online measurement of pulsating small flow rates.