A fall-down alarm system includes a contact detection unit, a non-contact detection unit and a fall-down evaluation unit connecting respectively to the contact detection unit and non-contact detection unit. The contact detection unit and non-contact detection unit respectively detect an abnormal detected shape of an object and abnormal life symptoms of the object, and then the fall-down evaluation unit determines a fall-down condition and sends a trigger signal to request assistance. Through the contact detection unit and non-contact detection unit respectively detecting the shape and life symptoms of the object, the erroneous fall-down judgment can be reduced.