To avoid the pre-excavation of retreat roadway and the setting of protective coal pillars in deep L-shaped stopes, this study on the backfilling-roadway retention control technology for the retreat roadway is of great significance. It is crucial for significantly improving the recovery rate of coal resources and ensuring the safe and efficient mining of deep irregular working faces. In this paper, the theory of continuous curved beams was applied to analyze the relationship between the backfilling rate, the burial depth and the deformation curvature of the roof overburden for the surrounding rock of the retreat roadway. And the backfilling strength calculation method of the surrounding rock of the retreat roadway was given. The ratio control method for backfilling gangue and modified backfilling materials is proposed. A long-distance transportation control system for backfilling gangue and modified slurry, both above and below ground, was built on site. An integrated surrounding rock control technology was developed for the relocation of the inner section of the L-shaped stope, combining real-time support, backfilled and roadway-side support. Field applications show that the proportion control of backfill gangue and modified slurry has achieved long-distance, rapid, and quantitatively controlled transportation of filling materials. With the maximum deformation of the surrounding rock in the retained roadway section measuring only 99 mm. During the directional transition phase of the deep L-shaped stope, the strength of the backfill body and the stability of the surrounding rock of the retreat roadway has been significantly enhanced.