Abstract: According to the bolt failure problems caused by the over large bed separation occurred by the deformation incoordination of the roadway roof strata, an elastic mechanics model of the bolt additional stress occurred by the roof bed separation was established .According to the bolt pulling load to the bolt function mechani sm during the relative movement of the strata, the stress distribution mode of the anchored mass under the roof bed separation function was obtained.The analysis foun d that under the condition of the same roof bed separation location, the higher roof bed separation value, the higher the additional stress occurred from the bolt by the r ood bed separation would be.Under the condition of the same roof bed separation value, the stress at the center of the bolt would be minimum, the additional stress occ urred closed to the boundary roof bed separation would be higher and the axial force and shearing stress of the roof bed separation location and the anchored mass wo uld be in a nonlinear relationship.