In response to the problem of serious deformation and damage of the surrounding rock during the service period of the reused roadway, the influence of lateral mining stress on the reused roadway is analyzed, and the deformation law and damage mechanism of the surrounding rock transportation of the reused roadway are revealed. The support strategy of using strong and flexible pier pillar to supplement the support of the roadway is proposed, and the support strength of the joint support body of "coal pillar - in-roadway support" is analyzed by establishing the mechanical model of broken reused roadway slab and pier pillar support, and theoretically calculating the support force load requirements to be satisfied by the pier pillar. The design and application of flexible piers were carried out in terms of support environment, material selection of filling body, structural design of support body and construction process, taking 3306 haulage road of Wangpo coal mine as the actual background. The field monitoring results show that: the deformation of the roadway surrounding rock within the overrun working face of the reused roadway is small, and the influence range is 200m of the overrun working face; the deformation within 50m of the lagging working face is the area of rapid growth of deformation, which should be focused on maintenance. By using flexible strong pier column in-road support can effectively alleviate the problem of serious deformation of the surrounding rock of the reused roadway and keep the deformation of the roof plate at a low level.