The　epistemic　uncertainty　of　geological　condition,　hydrological　condition,　and　human　factors　causes　the　risk　assessment　result　of　metro　construction　to　be　imprecise.　To　reveal　the　epistemic　uncertainty,　a　probabilistic　risk　assessment　approach　for　metro　construction　is　proposed　based　on　the　credal　network.　The　epistemic　uncertainty　of　risk　factors　is　described　by　prior　probability　and　conditional　probability.　Based　on　the　scarcity　of　available　data,　prior　probability　is　quantified　by　interval　probability　and　probability　box,　and　conditional　probability　is　qualified　by　imprecise　leaky　noisy-OR　model　and　imprecise　Dirichlet　model.　Taking　the　shield　tunnel　projects　of　Beijing　Metro　Line　14　as　the　research　object,　the　proposed　approach　and　the　conventional　approach　without　considering　epistemic　uncertainty　were　adopted　to　predict　the　risk　probability　of　surface　settlement　caused　by　shield　tunnel　construction.　The　predicted　results　were　compared　with　the　statistical　probability　derived　from　Peck　formula　and　the　field　monitoring　data,　which　verifies　the　rationality　and　effectiveness　of　the　proposed　approach.　(C)　2022　American　Society　of　Civil　Engineers.