This paper indicates that the current estimated index system college libraries in the age of digital library under the network circumstance has lagged obviously behind the demand of the time development, and the necessity to reconstruct the estimated index system of college libraries, the guiding of fully new estimated index system with the modern index and the developing principle of the navigation library are put forward. And combined with relevant estimated index of college library in“Qualified Estimated Index System of Undergraduate Course Work in Comprehensive University”, the modern estimating indexes in the estimated index system of college libraries are cited and the methods to be improved for relative projects are also discussed.