The　power　supply　capability　serves　as　a　pivotal　element　in　the　operational　evaluation　of　subway　traction　power　supply　system.　The　results　can　offer　critical　insights　for　the　formulation　of　preliminary　operational　strategies　and　train　scheduling　plans.　This　study,　grounded　in　the　national　standards　of　the　subway　industry,　identifies　key　indicators　for　the　evaluation　of　power　supply　capability　and　subsequently　designs　a　comprehensive　evaluation　framework　for　the　power　supply　capability　of　subway　traction　power　supply　system,　considering　the　boundaries　of　each　indicator.　Moreover,　by　integrating　the　power　supply　capability　of　the　subway　traction　power　supply　system　with　the　train　departure　intervals,　a　robust　method　for　evaluating　power　supply　capability　and　a　procedure　for　computing　the　maximum　power　supply　capability　are　established.　This　facilitates　the　real-time　evaluation　of　power　supply　capability　under　various　operational　plans　of　the　subway　traction　power　supply　system　and　the　determination　of　the　maximum　power　supply　capability.　The　method　proposed　in　this　paper　can　visually　and　accurately　display　the　situation　of　the　system,　providing　a　reference　for　the　evaluation　of　subway　operation.　©　The　Author(s),　under　exclusive　license　to　Springer　Nature　Singapore　Pte　Ltd.　2025.