In the automated production process of cigarettes, it is inevitable to encounter some malfunctions on a certain production line, and each malfunction will affect the quality and output of cigarette products. In order to ensure the quality of cigarette products, this article designs a warning function based on PLC and iFIX operating software on the cigarette production line. By analyzing historical and real-time data, a warning model is established using the process capability index CPK and setting warning thresholds. Intelligent warnings are given for unqualified data or other problems, and presented in the form of interface prompts. Transforming fault handling into pre warning, reducing losses caused by faults, ensuring stable quality and flow of each process (section) during the tobacco production process, uniform moisture and temperature of tobacco products, and meeting process requirements. The product is always in a highquality state. The warning system studied in this article will be able to effectively solve quality problems that arise during tobacco production.