The present invention discloses control system and method of an IoT boiler. A control system of an IoT boiler according to the present invention includes: the IoT boiler that checks an operation state to transmit state information, and senses whether or not a fault occurs through a sensor to transmit fault information; a manager terminal that includes a boiler control application for monitoring and controlling the IoT boiler, monitors a state of the IoT boiler, receives control information for controlling the IoT boiler from a manager, and transmits the control information; and a central management server that is connected to the IoT boiler and the manager terminal through a network, periodically or non-periodically receives and stores the state information of the IoT boiler from the IoT boiler, and receives the control information for controlling the IoT boiler from the manager terminal to perform control of the IoT boiler.