Abstract: In order to solve the scientific estimation of mechanical parameters of randomly distributed joint surfaces, in the laboratory, fractured rock blocks with different particle size gradations are selected to compress and obtain compacted solid specimens with different compaction rates; uniaxial compression experiments are carried out on compacted solid to record its axial stress-strain curves and analyze the probability distribution function and range of joint trace length; secondly, through orthogonal test and numerical simulation, the uniaxial compression numerical model was constructed, and the joint mechanical parameters of the simulated curve closest to the experimental axial stress-strain curve were selected as the joint mechanical parameters of the compression body. Finally, the roof stability of regenerated roof roadway under different degrees of compaction is studied by using the mechanical parameters of joints obtained from the actual site. It is concluded that the recycled roof is more stable when the particle size of the crushed rock is smaller and the compaction rate is higher.