Abstract: In view of the marked "Fuzziness" in the factors that have effect on the problems of rock mechanics, the deformation failure of rock mass in mining engineering is studied by using the Fuzzy mathematical theory in the paper. In accordance with the deformation failure of rock mass in open-pit mines, by applying the theory of Fuzzy probability measures, the Fuzzy probability formula is derived for the deformation failure of rock masses, and the numerical method is given to calculate the Fuzzy probability. The ...