Aming　at　the　current　problem　that　Electronic　whiteboard　positioning　has　the　poor　accuracy,　we　propose　an　improved　UKF　positioning　algorithm.　Through　adding　time-varying　fading　factor　to　the　standard　UKF　algorithm,　such　method　can　significantly　reduce　the　influence　of　outmoded　data　on　the　current　estimation　value.　Meanwhile,　by　adding　adaptive　adjustment　factor　to　alter　filtering　gain　to　control　the　divergency　and　improve　the　efficiency　of　algorithm　and　the　stability　of　data.　The　MATLAB　simulation　experiments　show　that　the　UKF　algorithm　can　be　applied　in　Electronic　whiteboard　positioning,　and　the　improved　UKF　algorithm　proposed　in　this　article　can　effectively　improve　the　accuracy　of　Electronic　whiteboard　positioning.　©　2014　IEEE.