In order to improve the weighing accuracy and realize the automation of batching process, a set of automatic weighing and batching equipment based on PLC is designed. The equipment includes three sets of silo assembly, which can store and supply different solid materials according to the formula. The function of control system includes formula management, parameter debugging, automatic weighing, alarm display and so on. The material feeding process is not only divided into coarse feeding and accurate feeding, but also introduces compensation coefficient,which effectively improves the weighing accuracy. By analyzing the test results, the equipment improves the weighing accuracy, it can reaches 96.7% that the probability of each material weighing error within the range of ±3 g.