Abstract. Mass transit line network’s option is a fuzzy optimization problem. Its line network evaluation is multi-objective and multi-hierarchy and the evaluation subsystems are incompatible. First, considering the urban development coordination, construction implementation, rationality of urban mass transit line network structure and comprehensive effect, researches established the appraisal index system of urban mass transit network using an assistant decision-making tool of system-analysis. Second, the study established extension and fuzzy optimization model with a vague idea of fuzzy mathematics, the knowledge of extenics and TOPSIS, explored the fuzzy and incompatibility issues on urban mass transit line network evaluation. The study introduced negotiation theory into weight construction, expanded single AHP to multi-experts weighting methods and combined it with entropy theory to form a new weight construction method. Last, as a validation, Changsha urban mass transit line network were evaluated and verified the feasibility and practicality of the model and method mentioned above.