The invention provides an alarm method and system based on the Internet of things. The method includes the following steps: when human bodies are detected in a machine room, acquiring the number and identity of users entering the machine room; acquiring the health data of each user, establishing a corresponding health data file for each user, analyzing the health condition, and if abnormal healthdata is found, informing the corresponding user to pay attention to health abnormality in one or more ways, such as giving a voice prompt in the machine room, giving a visual prompt in the machine room, sending corresponding prompt information to the social account of the corresponding user, and sending corresponding prompt information to the mobile phone of the corresponding user; and if the abnormal health data is judged to belong to a serious situation in a preset serious situation list, automatically sending alarm information to a rescue organization meeting preset conditions. Therefore, the staff in the machine room can raise the alarm much more conveniently.