The invention discloses a method for prolonging the service life of a belt in a belt conveyor. The method specifically comprises following steps: firstly, a spindle is machined and manufactured; secondly, a waste belt is tailored into multiple cakes with different diameters; thirdly, the middle portion of the cake-shaped waste belt is hollowed, and is arranged on the surface of the spindle in a sleeving manner; fourthly, bearing pedestals and bearings are arranged at the two ends of the spindle and are combined to buffer rubber wheels; fifthly, an original supporting wheel support in the beltconveyor is dismantled, the buffer rubber wheels are arranged below the belt, and fastening and fixing through a bolt are achieved. The method has the beneficial effects that the buffer rubber wheelsserve as supports to replace original groove type supporting wheel supports, impact force between the belt and the support can be effectively reduced, the service life of the belt and the service lifeof a chute can be prolonged, the service life can reach one to two years if maintaining is in time, and workloads are reduced for production and overhauling.