Marching　Cubes　algorithm　is　a　classical　algorithm　of　the　surface　rendering,　but　the　traditional　MC　algorithm　has　low　computing　efficiency,　and　generate　a　great　number　of　triangular　patches.　This　paper　proposes　an　improved　method　that　combines　with　traditional　MC　algorithm.　We　replace　the　linear　interpolation　using　the　mid-point　selection,　establish　the　index　of　the　intersection　point　of　the　cube　edge　and　isosurface　to　improve　the　speed　of　image　reconstruction.　Edge　contraction　method　is　used　to　reduce　the　number　of　triangular　patches.　It　was　proved　by　the　instance　that　the　improved　algorithm　could　extract　isosurface　and　improve　the　user　interaction　efficiency.　©　2010　IEEE.