Abstract: In order to solve the stability problem of large section top coal roadway in No.4 coal seam of Longquan Coal Mine, taking the return airway of 4203 working face of Longquan Coal Mine as the research object, the roadway stability is studied by the combination of theoretical analysis, numerical simulation and field measurement. Firstly, the mechanical analysis model of roadway rock stability is established, the calculation formula of top coal crushing position is deduced, and the main factors affecting top coal failure are determined. Secondly, UDEC-Trigon model is used to analyze the stress, plastic zone and surrounding rock displacement of roadway under different top coal thickness. The results show that the shear failure of roadway roof is related to the internal friction angle of rock and the friction angle between rock blocks（ｓｕｒｆａｃｅｓ）, and the failure position is at the shoulder angle of two sides of roadway. By comparing the supporting effects of supporting schemes under different top coal thickness, the comprehensive control technology of surrounding rock for timely supporting roadways with high pre-stress and high strength bolt and cable in return airway of 4203 working face was proposed. The optimized support scheme was applied in the field, and the measured maximum deformation of roof and floor was 104 mm, and the maximum deformation of two sides was 86 mm, and the implementation effect was significantly improved.