Underground tunnel construction, particularly in gas-prone areas, poses significant challenges due to its scale, complexity, and high-risk environment. Safety issues, especially gas-related incidents, are critical factors that influence the overall quality and progress of tunnel engineering projects. At the intersection of standard tunnels and gas-bearing zones, the implementation of effective safety management and ventilation strategies becomes paramount. The system integrates multiple factors derived from engineering practice to evaluate and classify potential gas leakage hazards accurately.Experimental application of the model at a high-risk tunnel construction site demonstrated its practical value. The assessment results, ranging from levels III to IV, corresponded with the site's actual conditions—characterized by high oil and gas content, frequent gas overflow, and elevated excavation risks. These findings confirm the reliability and sensitivity of the NCM-based approach in identifying and quantifying gas safety risks.