A fall detection system includes a wearing apparatus for wearing by a user and a processor connected to the wearing apparatus. The wearing apparatus is set with an inertial sensor for detecting user motion data. The processor is connected with the inertial sensor of the wearing apparatus. When the user's fall state is recognized, further obtaining the motion data of the user at the time of the stand by the inertial sensor and comparing the motion data according to a normal posture condition and/or an abnormal posture condition in a database to determine damage severity of the user.
