Koji-making is an important part in the production of soy sauce. The traditional means of yeast pool ventilation starter depends on the experience of staff to control the environment of yeast antrum, which koji way automation level is not high, koji product stability is not guaranteed. This paper proposes a design method of soy sauce koji-making control system based on ARM processor S3C2440. It mainly consists of embedded microprocessor S3C2440, power conversion circuit, data storage circuit, display circuit, communication circuit composition. The Linux operating system is used to achieve the automatic control of the traditional process of making koji. The staff can judge the bending machine, fan working time directly through the soy sauce making koji control system, which improves the traditional production of soy sauce production level, and ensures the stability of the quality of the product.