Fast-growing　logistics　demand　aggravates　traffic　congestion　while　posing　great　pressure　on　the　urban　ecology.　A　prospective　solution　is　to　split　extensive　goods　movement　from　roads　to　underground,　especially　the　metro　systems.　This　paper　proposes　a　simulation-based　approach　for　supporting　the　operational　decision-making　of　the　metro-based　urban　underground　logistics　system　(M-ULS).　Based　on　a　holistic　concept　of　M-ULS　network　archetypes,　two　integration　schemes　of　passengers　and　freight　transport　in　metro　network　(i.e.,　collinear-detached　metro　and　the　collinear-trailer　metro)　are　explicated.　Next,　mechanisms　of　metro　freight　service　assignment,　standardized　packing,　timetable　coordination,　and　rolling　stock　circulation　are　proposed　and　formulated　considering　multiple　criteria　and　travel　patterns.　A　data-driven　discrete-event　simulation　model　with　user　interface　is　developed　to　acquire　the　real-time　operating　states　of　M-ULS　in　36　tested　scenarios.　Experiments　conducted　on　the　Nanjing　Metro　case　show　that　the　proposed　method　can　effectively　capture　the　dynamic　performance　and　bottlenecks　of　network　operations　in　different　operating　periods　and　environments.　The　two　considered　system　schemes　show　respective　advantages　in　terms　of　freight　demand　backlog,　capacity,　traffic　flow　control,　and　efficiency,　both　of　which　have　good　compatibility　with　metro　passenger　services.　The　value　of　this　paper　is　to　provide　a　quantifiable　design　framework　and　assessment　paradigm　for　M-ULS　operations.　It　also　offers　new　insights　for　solving　＂big-city　diseases＂　and　the　potential　innovations　of　urban　underground　space　and　metro　systems.