An automatic control system of sampling package for sample coal was designed based on controller(PLC) according to the realities of sample coal powdery materials. The system can realize automatic control of random sampling, auto-weighting, auto-packaging, and auto-sealing off functions. It has the characteristics of less waste, convenient control, zero point self-tuning and dynamics weighing measurement. It can be used in sampling weighing package of sample coal. Various performance indicators were proved to stable and reliable by field test.