Abstract: In view of the determination of the width of narrow flexible formwork concrete roadway beside gob-side entry retaining in shallow seam, this paper takes the 15301 working face of Wujiagou coal mine of China Coal Science and Technology Group as the engineering background, the method of combining numerical simulation, theoretical calculation and engineering example is adopted to carry out the research. The results show that when the width of flexible formwork wall is more than 1.5 m, the stress concentration of wall and surrounding rock, the deformation of roadway surrounding rock tend to be stable, and the stability of roadway surrounding rock is better. Considering the economic safety benefit, the 1.5 m wall width is selected as the construction condition. The engineering application result shows that the flexible formwork concrete technique can fully ensure the roadway surrounding rock stability, and the roadway side support effect is remarkable, to improve the safety of the mine as a whole, the technology of retaining gob-side entry with flexible formwork support has a good prospect of popularization.