Aiming at the problems of backward monitoring means and low information level of heat pump low-temperature circulating food dryer, a monitor and control system of heat pump low-temperature circulating food dryer based on the Internet of things was designed and developed. The architecture design of the system used perception layer, transmission layer and application layer, and the system took programmable logic controller (PLC) and HMI touch screen as the core to design and develop a control system to realize real-time monitoring, graphical display, safety protection and automatic control of dryers and heat pumps. The server system framework was developed by Linux CentOS system. The data connected by EG8000mini module was sent to AP base station and stored in database. Users can remotely monitor and control the heat pump low temperature circulating food dryer through computer or mobile APP. The experimental results showed that the communication success rate of the system was higher than 98%, and the average absolute error of real-time detection of ambient temperature, hot air temperature, hot air humidity and hot air wind speed was 0.3℃, 0.26℃, 1.2% and 0.47 m/s, respectively, which can meet the remote monitor and control requirements of heat pump type low temperature circulation dryer.