The invention discloses a quantitative method for cable body damage based on natural frequency change, comprising the following steps of: respectively arranging an acceleration sensor in each cable ora hanger rod by hierarchically cutting the wire of the cable body; collecting a lateral vibration acceleration signal of the cable or the hanger rod; obtaining the cable vibration natural frequency,the force, the length, the unit length quality data and the bending rigidity of the cable; and forming a vibration balance equation of the cable by a balance equation of the force and a moment balanceequation. According to the quantitative method for the cable body damage based on the natural frequency change, the damage quantitative error can be within 10%.