In this paper, we present an automatic monitoring system for an industrial catalytic reduction method to deal with the needs in the analysis of the efficiency of emissions of dichlorophenol and volatile organic compounds (VOCs). The system uses automatic measurement, control, and hardware and software design techniques. This allows the user to set the control parameters for the catalytic reaction as required and to perform monitoring procedures for the reduction reaction of dichlorophenol and VOC catalyst. The system can control the flow of the participating gas and the evaporator temperature for the mixing of gases and dichlorophenol or VOC mixture, and then send it to the catalyst bed for three-stage temperature-monitoring operations. At the same time, the system can automatically record the information related to the catalytic reaction process and establish an analysis curve to be used as the basis for analyzing the reduction efficiency of the dichlorophenol and VOC catalyst.