Basing on pressure-state-response(PSR) model,we screened indices including ecological pressure of railway construction,nature reserves status and countermeasures response effectiveness,determined weights of each index by AHP,and then constructed an evaluation system based on triangular fuzzy numbers.The results showed the impact rank of the proposed railway on the environment of Shapotou Nature Reserves could reach as low as grade Ⅰ,suggesting reasonable route selection and scheme design,effective protection recovery measures and acceptable influences on the environment.More importantly,the method of combinating AHP and triangular fuzzy number could overcome the shortcomings of single factor evaluation,the difficulty quantification of assessing indices,and poor comparability.The evaluation results were found consistent with field survey and expert review conclusions,which implies that the proposed evaluation system is of good feasibility and applicability.