Abstract: In order to master the stress and strain characteristics of gangue filling materials, three groups of primary gangue samples with particle size below 80 mm in Yungang Coal Mine were selected, and six groups of gangue samples with different particle size grading were designed. The large diameter loading container was processed, meanwhile, the compression experiment was carried out by using TAW-3000 electro-hydraulic servo control system. The results show that the compression process of gangue can be divided into three stages: rapid growth, nonlinear growth and slow growth; the strain is mainly caused by the movement and breakage of rock blocks, which leads to the filling of the space between the blocks, but not the deformation of the gangue itself; under the same axial stress, the strain decreases with the increase of the proportion of small particle size in the sample, and increases with the increase of the proportion of large particle size gangues; the strain of primary gangue samples is in the middle range of the designed grading groups. The relationship between the strain of gangue samples and the proportion of gangues with small particle size is obtained, which can provide reference for the design and research of filling and mining of gangue.