Abstract:The deformation characters of the broken rocks are the important factors that affect the roof caving and surface subsidence above goaf in coal mining. With a compaction device,especially designed for broken rocks,the deformation character tests of water-saturated three broken rock samples (coal,shale and sandstone) were tested in a MTS815.02 test system. It was found that stress-strain properties of the samples of broken rocks depend on grain size and rock strength. The results show that the stress-strain relation can be approximated as a power function. In addition, the strains of specimens decrease with the increase of strength under the same stress conditions,the strain increase of course grained specimens is smaller than that of fine grained specimens in the first period of loading process,and the water-sutured broken rock specimens undertake larger stains than the rock specimen of natural water content under the same level of stress. These test data are useful for further study.