With some considered data, such as preventive experiments result, working surroundings, operation records, maintenance records, and so on, by using the method of analytic hierarchy process, an improved fuzzy synthetic evaluation assessment model for cables was proposed, the relative interiority indicator was adopted, and different methods were used to determine the membership functions for qualitative indices and the quantitative indices. Through assessing the layer and sub-layer factors, the comprehensive operating condition of cables can be achieved. Based on the actual monitor data for a 220kV cable in power tunnel, analysis result shows the proposed assessment model was correct and effective.