Firstly,　a　multilevel　trust　algorithm　for　MANET　(mobile　ad　hoc　networks)　is　presented　in　this　paper　and　the　trust　level　is　defined　as　a　three-tuple　type　in　this　multilevel　trust　algorithm.　The　paper　introduces　the　multilevel　trust　into　MANET,　thereby　controlling　restricted　classified　information　flows　among　nodes　that　have　different　trust　levels.　Secondly,　the　infrastructure　of　MANET　that　suit　to　our　multi-level　trust　is　presented.　Some　conclusions　are　given　at　lastly.