Compared with conventional structures， transportation hub buildings， as critical nodes in urban transportation networks， show their large scales and functional complexity. To address the lack of specificity in existing methods for evaluating post-earthquake functional loss， a novel evaluation method based on component functional assembly is proposed for typical transportation hub buildings. Considering the uncertainty in component functional loss， a mapping relationship between damage states and functional loss is established. Logic trees of floor-level functional loss for passenger bus stations are established by applying fuzzy operators. Given the functional correlation between floors， the TrueSkill algorithm is adapted to quantify the importance weight coefficients， and the functional loss quantification from floors to the overall structure is established. Finally， the proposed method is applied to the post-earthquake functional loss assessment of a three-story reinforced concrete frame structure passenger bus station， demonstrating the feasibility of the proposed method.