Abstract: Aiming at the problem that insufficient filling width of filling bodys beside roadways in gob-side entry retaining causes the instability of roadway and the large deformation of roadway in Yuwu Mining Area of Lu’an Group, we analyzed the stress characteristics and deformation characteristics of filling bodys beside roadways of the fully mechanized tail lane, used FLAC^3D to simulate the deformation characteristics of surrounding rocks in gob-side entry retaining, and determined the optimal filling width of filling bodys beside roadways. Results show that the effect of filling body beside roadways on the surrounding rock of roadway in a short time can achieve high strength, high resistance state, and has a good deformation performance, so as to realize the common bearing of the surrounding rock with non-mining slope, filling body and falling waste rock; when the width of the filling body of the roadway is 1.5 m, the width of the filling body is transferred from unstressed concentration to less stress concentration, and the peak stress change is most obviously increased from 8.3 MPa to 12.6 MPa, in this case, the surrounding rock deformation is smaller.The measured results of the two observation points show that the convergence amount of roof-to-floor is 331.3 mm and 280.7 mm, respectively, and the convergence amount of two sides is 225.4 mm and 171.7 mm, respectively. The roadway rock deformation is mainly roof subsidence and gob-side retaining lane along the roadway basically meets the surrounding rock control requirements.