A　vision-based　Augmented　Reality　computer　assisted　surgery　navigation　system　is　presented　in　this　paper.　It　applies　the　Augmented　Reality　technique　to　surgery　navigation　system,　so　the　surgeon＇s　vision　of　the　real　world　is　enhanced.　In　the　system,　the　camera　calibration　is　adopted　to　calculate　the　cameras　projection　matrix,　and　then　make　the　virtual-real　registration　by　using　the　transformation　relation.　The　merging　of　synthetic　3D　information　into　user＇s　vision　is　realized　by　texture　technique.　The　experiment　results　demonstrate　the　feasibility　of　the　system　we　have　designed.