Organic　Rankine　cycle　(ORC)　can　improve　the　fuel　efficiency　of　internal　combustion　(IC)　engine.　However,　the　dynamic　characteristics　of　ORC　system　in　driving　conditions　are　not　only　affected　by　variable　high-temperature　waste　heat　source,　but　also　have　strong　coupling　correlation　between　operating　parameters　and　performance.　Under　the　superimposed　influence,　the　performance　of　vehicle　engine-ORC　combined　system　has　obvious　nonlinearity　and　uncertainty.　This　paper　first　constructs　a　vehicle　engine-ORC　combined　system　model　for　the　driving　conditions.　Based　on　different　driving　cycles,　the　combined　system　is　verified.　The　influence　of　ORC　system　on　engine　performance　in　driving　conditions　is　evaluated.　The　synergetic　influence　laws　of　operation　parameters　in　driving　conditions　is　systematically　analyzed.　Based　on　vehicle　engine-ORC　combined　system　for　driving　conditions　model,　simulation　model　with　different　coupling　units　and　multi-objective　optimization　algorithm,　this　paper　proposes　an　integrated　multi-objective　optimization　framework　of　combined　system　with　complex　driving　conditions.　The　real-time　optimization　of　integrated　system　performance　in　driving　conditions　is　realized.　The　trade-off　and　uncertainty　correlation　between　combined　system　performance　in　driving　conditions　are　analyzed.　Finally,　the　improvement　of　IC　engine　performance　by　ORC　system　in　driving　conditions　is　quantitatively　evaluated.　The　nonlinear　optimization　framework　proposed　in　this　paper　can　provide　a　practical　solution　for　the　analysis,　evaluation　and　real-time　optimization　of　vehicle　engine-ORC　combined　system　performance　in　driving　conditions.