Abstract: This paper analyzes the use effect of the dry oil injection control circuit of the 320MW unit coal mill of Shaanxi Coal Power Xinyang (huayu) Co.,LtD after being connected to DCS. The transformation has a significant effect on saving oil,which not only contributes to the comcony’s energy conservation ,consumption reduction, cost reduction and efficiency increase , but also introduces the dry oil injection device into DCS joint control, improving the safe operation level of the coal mill system and saving human and material resources, this provides reference experience for the dry oil injection control of similar units.