Abstract: In order to study the instability mechanism of roof roadway under the sprinkling roof in water-storage area, the transportation roadway in No.2104 working face of Heilong Mine was taken as the research background, through field measure, mineral composition and water quality analysis, rib rock disintegration and mechanical property test, FLAC3D numerical simulation and other research methods were used to study the instability characteristics and mechanism roof of No.2104 transport roadway. The results showed that the instability of the roof roadway under the water-storage area was affected by multiple factors: ① The roof of the roadway was soft rock developed by clay minerals, and the expansive soft rock Kaolinite accounted for 23.2%～32.2% of the total rock composition, and the surrounding rock strength was low; ② Due to interaction between the acidic mine water and the mineral composition of roof rock mass, the mineral composition and microstructure of roof rock mass change, the lateral and longitudinal cracks increased greatly, and the rock mass was muddy weakened. The uniaxial compressive strength of the surrounding rock decreased by 35%～38%, the tensile strength decreased by 24.5%～53.7%, the cohesion decreased by 24.1%～44.7%, and the internal friction angle decreased by 7.9%～12.3%. The modulus decreased by 19.6%～43.4%, and the Poisson's Ratio increased by 10.0%～16.7%. ③ During the process of excavation, the roadway was affected by the mining disturbance, the stress concentration, and the plastic zone damage range increased by 21.4%～90.0%, and the roadway deformation increased by 16.6% ～65.6%, the stability of the roadway was poor; ④During the mining, the roof of the roadway was subjected to repeated immersion and weathering, the cracks of the surrounding rock developed, and the instability of the roadway was intensified.