A system for monitoring bike riding safety and physiology of a bike rider is disclosed. The system includes an informing module, a global positioning system module, a safe riding recognition module, a physiology signal detecting module and a processing module. When the safe riding recognition module detects an unusual riding, the safe riding recognition module will generate an unusual riding informing signal. The processing module recognizes whether an accident has happened by analyzing a physiology detecting signal, a positioning signal and the unusual riding informing signal. When the processing module recognizes that an accident has happened, the processing module drives the informing module for informing that an accident has been happened. Therefore, once an accident happens, the system can ask for help automatically so as to rescue the bike rider injured by the accident as soon as possible.
