The invention discloses a cable body damage monitoring method and system for an inhaul cable type bridge provided with a main longitudinal beam. According to the method, finite element analysis software, bridge on-site modal monitoring, cable force monitoring and single cable body broken wire test are used; monitoring of inhaul cable type bridge damage conditions is achieved through bridge modal monitoring data, inhaul cable force monitoring data, single cable body broken wire test data and corresponding calculation and analysis theories and simulation methods. By means of the method, the wirebreakage amount of a single cable body can be accurately calculated, the inhaul cable damage condition of the inhaul cable type bridge with the longitudinal beam system can be monitored in real time,an alarm is given timely and accurately once the wire breakage amount exceeds an early warning value, the safety of the inhaul cable type bridge is improved, and potential safety hazards are eradicated.