In response to the problems of large displacement of the roof to floor andlarge deformation failure of the backfill body, with the gob-side entry retaining by roof cutting of working face Ⅲ635of Zhuzhuangcoal mine.This paper proposes a composite load-bearing of the backfill body and gangue during gob-side entry retaining. The theoretical method is used to analysis the mechanical model of the roof considering the combined support of backfill body and gangue, and the deflection equation of the roof is derived. Using a combination of numerical simulation and field practice, the deformation mechanism and stress evolution law of the surrounding rocks was studied, and revealing the synergistic load-bearing effect of the backfill body and gangue during gob-side entry retaining. The results show that:after the adoptionof the composite load-bearing of the backfill body and gangue during gob-side entry retaining, the vertical stress peaks of the solid coal and the backfilling body are reduced by 28.3% and 44.4% respectively. The deformation of the roof to floor of the roadway is reduced by 58.2%. The field application results show that the technology effectively controls the roadway deformation and provides a reference value for the control of the surrounding rock of gob-side entry retaining under similar conditions.