Abstract: In order to promote the coordinated development of mountain railway project and water resources along the route,the coupling coordination model and multidimensional critical regulation model were proposed to analyze the coordinated relationship between mountain railway project and water resources and optimize the regulation.Firstly,based on the analysis of the coupling relationship between mountain railway project and water resources,the coupling coordination index system was constructed from the perspective of water conservation,and the comprehensive weight of each index was determined by using the combination assignment method.Secondly,the coupling coordination model was used to calculate the coupling coordination development state of mountain railway project and water resources system,and the main control factors were determined according to the impact of indicators on the complex system,combined with the multidimensional critical regulation model to regulate the main control factors.Finally,taking a section of a mountain railway project as an example,the coupling degree of the railway project and water resources complex system is 0.8968,and the coupling coordination degree is 0.4700,indicating that the interconnection between the railway project and water resources along the line is strong,the degree of coordinated development is in the primary coordination state.After the main control factors of tunnel water influx,bridge pit precipitation,surface water development and utilization,groundwater development and utilization were regulated by the multidimensional critical regulation model,the system entropy value decreases from 0.3024 to 0.2417,and the system entropy value decreases,and the system tends to be stable,indicating the coordination degree between the mountain railway project and the water resources system becomes better and the system is developing in the direction of orderly coordination.This study verifies the validity of the selected model and can provide a new idea to promote the coordinated development of railway project and water resource system in similar mountainous areas.