Railway traffic is a strip of buildings, its impact on the natural environment along the line is very complex, according to this feature, in the evaluation of the environmental impact of the railway, the "goal-indicator hierarchy" model is adopted, the analytic hierarchy method (AHP) is used, qualitative and quantitative indicators are combined, some important individual indicators are screened out and their weights are determined, and then the elimination and selection transformation method (ELECTREII.) is used to establish four matrices of priority, inferiority, ideality and proportion of inferior indicators. Finally, according to the determined threshold value and the drawn priority map, the schemes are compared and sorted until the optimal scheme is selected. An example is given at the end of the article for verification.