Abstract: The principle of white light digital speckle correlation method (DSCM) is presented in this paper, and deformation localization of rock and coal is discussed by using white light DSCM. The starting point of deformation localization is gauged, and the evolution process of localization is demonstrated, and for the first time, the width of deformation localization is obtained by experiment. By experimental and theoretic analysis, the results of investigation indicate that the white light digital speckle correlation method is very useful in studying the non homogenous evolution process of rock, and by this method, the microscopic parameter of rock can be gauged.