Based on geotechnical investigation on phyllitie in Changbei,three influenceing factors,including rock materials,characteristic and strength of rock mass,that have seventeen secondary items,are selected,and which weight are made certain by the Analytic Hierarchy Process.In the end,weathering degree of phyllitie in Changbei is judged quantificationally by fuzzy Synthetic Evaluation,and the method are applied to an work example with satisfying results.