Mobile　robots　often　operate　in　dynamic　environment,　such　as　an　exploratory　robot　or　one　that　must　move　to　a　goal　location　without　the　benefit　of　a　floorplan　or　terrain　map.　In　this　case,　the　robot　needs　to　be　able　to　replan　quickly　as　the　knowledge　of　the　environment　changes.　The　process　of　robot　navigation　in　dynamic　environment　mainly　includes　three　steps:　first　translate　the　configuration　space　that　the　robot　and　obstacles　exist　in　into　2D　Cartesian　Grid　by　Quadtree　method;　second　design　the　sub-goals　given　the　global　map,　start　and　goal　points　by　A*　Algorithm;　last　replan　the　path　between　two　adjacent　sub-goals　by　improved　D*　Lite　Algorithm　when　the　environment　changes.　It　is　able　to　replan　faster　than　planning　from　scratch　since　it　modifies　its　previous　search　results　locally　and　enables　robots　adapt　to　the　dynamic　environment.　The　simulation　results　that　are　reported　show　that　the　mobile　robot　navigation　method　is　efficient　and　feasible.　©2007　IEEE.