In order to find out the deformation law of roadway under the support of large deformation fiberglass bolt, a three-dimensional calculation model was established by using numerical simulation software, and the support effect of conventional fiberglass bolt and large deformation fiberglass bolt was compared and analyzed. The results show that when the goaf of the working face is squared for the first time and squared for the second time, the roadway shows a trend of inward contraction, and the plastic zone is mainly concentrated around the roadway. The horizontal displacement of the mining side and the settlement of the roof show a trend of gradually decreasing and then tending to be stable. When the goaf is first and second square, within the monitoring range, the maximum horizontal displacement of the mining side has reached the breaking displacement of the conventional FRP anchor rod, but it has not reached the breaking displacement of the large deformation FRP anchor rod. The conventional FRP anchor rod does not meet the support requirements, and the large deformation FRP anchor rod meets the support requirements.