A system for recognizing abnormal activity of human body using wearable electronic device and mixed reality technology, includes a first wearable electronic device, a plurality of second wearable electronic devices, at least one camera, and a judgement module. The system is suitable to be applied in any type of work environment, so as to monitor and determine whether a user (i.e., an operator or an employee) exhibits abnormal activities by referring a document of standard operating procedures (SOP), an operating manual and a document of safety operation standard (SOS), to reduce a rate of user mishandling, thereby achieving the enhancement of work efficiency and productivity.