In order to meet the needs of high precision and high efficiency of the pyrotechnic charge weighing, a high precision pyrotechnic charge weighing system based on programmable logic controller (PLC) was designed. The method adopts a mode of combining constant volume weighing and controllable vibration weighing, firstly uses a constant volume metering plate to add a large dose of medicament, then uses a PID algorithm to control a linear vibration mechanism to vibrate at a certain frequency, drives the medicament in an upper container to be added with a small dose with high precision along a material channel, judges the weight of the medicament, and rejects unqualified products. The results show that the measurement accuracy of the weighing system is less than 1 mg, and the weighing efficiency is high, which can meet the high precision weighing requirements of most of the pyrotechnics.