The design of an electrical fire monitor system in industry base on the PROFIBUS protocol was proposed, according to the demands of intelligent control system in industry. Modularization was adopted in this design and the whole system was divided into two module, monitor and protocol conversion respectively. The main circuit diagram of hardware and software was given and the human-machine interface of monitor system was designed by using configuration software of WINCC and STEP7 in this paper. The practical run result has proved the design was feasible, the system was reliable and timely and it had good extensibility.