Abstract: According to the characteristics of time-dependent damage and the threshold of accelerating damage,an evolvement equation of creep damage based on non-linear visco-elasto-plastic rheological model was established.Its correctness was validated by the tests on shear rheological results of slates of large and long water transfer tunnel at Jingping Hydropower Ⅱ.It was shown that the non-linear rheological damage model could not only reflect the whole rheology process of rock,but also describe efficiently the primary,stationary and tertiary rheological damages for slates under the conditions of different stresses.