Abstract: In order to solve the problem of roadway support for adjacent slopes from open-pit to underground mining, the fault fracture zone exposed in the inclined shaft construction process of open-pit to underground mining in Fuxin Gaohai Coal Mine was taken as the engineering background. According to the structural characteristics and quantitative characteristics of intact rock and debris in the fault fracture zone exposed on the spot, the discrete element calculation and analysis model of random polygon was established by distortion method, and the progressive failure law of surrounding rock displacement field and fracture field during roadway excavation was systematically studied. The results showed that the failure of surrounding rock of roadway started from the clastic structure of fault fracture zone, and the fracture developed from the vault to the slope toe of the slope, and the macroscopic fracture surface was formed between the two. The large area instability of surrounding rock and slope of roadway vault was induced. Finally, the reinforcement measures of roadway advance grouting and slope anchor were put forward. The engineering test showed that the reinforcement scheme was feasible. The research results could provide reference for roadway construction in similar strata.