This study characterizes the instability characteristics (e.g., deformation and failure) of roadway surrounding rock induced by repeated mining in close-distance coal seams. A dynamic model for repeated mining was established based on the force equilibrium principle, yielding a novel surrounding rock instability criterion. The deformation-failure laws and mechanical behavior of the surrounding rock under repeated mining were systematically investigated using 3DEC discrete element numerical simulation. Integrating these findings with field monitoring data, targeted stability control measures and an implementation scheme were developed. Key results demonstrate that: The proposed instability criterion index effectively characterizes failure modes under repeated mining; Instability occurs when the index > 0, while stability is maintained at values ≤ 0; Increasing the staggered distance between gate roadways in the upper and lower seams mitigates the influence scope of mining-induced roadway displacement and overlying interburden disturbance; Implementation of a staggered roadway layout combined with an intensive support scheme reduces post-support surrounding rock stress by 22.5%. These findings provide a theoretical basis and practical guidance for stability control in similar repeated mining engineering contexts.