This　paper　presents　a　key　frame　interpolation　method,　which　can　represent　swing　and　variable　motion　for　virtual　human　animation.　Based　on　motion　features　of　angles　between　bones,　key　frames　are　extracted　from　captured　motion　data　using　curve　simplification　method.　Key　frames　are　classified　through　motion　details,　and　different　interpolation　methods　are　used　to　compute　internal　frames　for　different　class.　Experiments　show　that　method　provided　by　this　paper　can　simulate　arm＇s　swing　and　variable　motion　animation.