Abstract: A status diagnosis system based on the internet of things (IoT) was designed in order to better guarantee the stable operation of the Heavy Ion Accelerator (HIRFL) of the Institute of Modern Physics, Chinese Academy of Sciences. In view of the large number and complexity of the devices in HIRFL, the IoT design architecture was used in this paper, various data were collected by a lot of sensors and transmitted to the database in the central control system through the network. The data were analyzed comprehensively by the control software running on the server, some reasonable advices were given and corresponding instructions were issued. According to the actual situation of HIRFL, a HIRFL state diagnosis system model was designed preliminarily, including the hardware and software. Some of the software is put online and tested in the actual operation, and a certain accelerator state diagnosis effects are obtained.