In　a　three-stage　dynamic　game　model,　the　article　studies　the　relationship　between　investmentinverted　commas　financing　and　product　market　competition　in　the　case　that　the　enterprise＇s　debt　financing　strategy　is　made　after　making　research　and　development　investment　strategy　under　uncertain　circumstance.　The　research　show　that　under　the　enterprise＇s　margin　income　increasing　with　market　demand　booming,　the　increase　in　the　enterprise＇s　debt　level　will　make　the　product　market　competition　more　intensively,　instead　the　opposite　is　true.　The　enterprise＇s　ex-investment　strategy　not　only　has　direct　and　indirect　effect,　but　also　affects　the　degree　of　debt-financing＇s　strategically　commitment　effect.　©2009　IEEE.