In this study, and along with the assessment of the environmental impacts of the Ahvaz-Shiraz railway, the ecological stability and environmental vulnerability of the proposed alternative for this project was evaluated. Firstly, the region’s ecological stability was assessed by triple formulas. Then, to assess vulnerability, the physical, biological, and socio-economic criteria were selected, provided and standardized and then for criteria prioritizing, the fuzzy analytical hierarchy process was applied. At the next stage, these layers were combined, and a vulnerability map of the region was created, dividing it into five classes. The results showed that 10.58 per cent of the area is very highly vulnerable, and 23.8 per cent is highly vulnerable. Finally, the route intersections with the five vulnerability classes were surveyed and the results showed that 4151 metres of the total path length (56,345 metres) crossed 7.36 per cent of land with very high vulnerability, and 14,189 metres of the total course length was cut with 25.18 crosses of great vulnerability.
