Abstract: This paper deals with the information value mehtod for stability study of large scale and high rock slopes of engineering for the first time. On the basis of engineering geological work of some hydroelectric station slopes, the information value of 8 factors and 77 conditions were computed. The information prediction values of 128 prognostic units were acquired. Finally, it was discovered that 53 units are unstability units in which 12 units belong to new prognostic unstability units. By instrumental observation, some new prognostic unstability units were confirmed. It shows that the information value method has important significance for removing the hidden danger of engineering.