Abstract: In order to study the strain distribution of the whole field of coal deformation and failure in the process of uniaxial compression tests on coal samples, we use TYJ-500KN computer controlled electro-hydraulic servo shear rheological test system and XTDIC 3D optical digital speckle system. According to the calculation results of the digital speckle, displacement evolution loading process of coal samples is studied. We get the conclusion that when the shear failure is in coal sample, digital speckle image displacement concentration appears earlier, and the displacement area is obvious. Through monitoring the whole process of coal loading failure, the digital speckle system can accurately predict the destruction of the form and the location of the sample. Therefore, for the destruction of coal samples, the analysis of digital speckle monitoring data can be used to predict the damage position of the sample, and it is also important to explore the location and distribution of coal sample damage.