For　the　problems　of　multidisciplinary　and　multiobjective　design　and　decision,　a　novel　method　was　given　using　game　theory　and　flexibility　mechanism　to　model　and　solve　the　problems.　The　coupling　relations　among　disciplines　or　targets　were　presented　by　mixed　game,　and　the　mixed　game　model　framework　and　the　corresponding　solving　methods　were　proposed.　Considering　the　influences　of　uncertainty　and　changes,　in　order　to　make　the　design　and　decision　be　flexible,　the　satisfaction　function　of　performance　was　introduced　to　express　the　flexible　design　requirements,　and　the　flexible　range　solutions　of　design　variables　were　sought　rather　than　a　point　solution　to　increase　product　flexibility.　The　flexible　range　solutions　were　in　the　feasible　design　spaces,　where　every　discipline＇s　performances　were　satisfactory　and　close　to　the　expected　values　and　had　good　stability.　Probabilistic　representation　was　used　to　model　the　corresponding　design　performance　changes,　and　design　preference　index　(DPI)　was　introduced　to　evaluate　the　flexible　design.　Finally,　a　gear　reducer　design　example　was　given　to　verify　the　feasibility　and　effectiveness　of　the　proposed　method.　©　2017,　China　Mechanical　Engineering　Magazine　Office.　All　right　reserved.