The pneumatic batching system adopts positive and negative two-way tracking, which further improves the tracking accuracy. After the batching operation, the weighing module constantly detects and tracks the position of the micro-switch to detect the machine, and after the signal is sent to the PLC through the program calculation, the positive and negative tracking of the motor is controlled by the PLC output, and the error of the packaging materials in the production process is found in time and accurately compensated and corrected, avoiding the waste of packaging materials. If the detection can not meet the technical requirements after tracking the predetermined number of times, it can automatically stop for inspection to avoid the generation of waste products.