Automatic　reconstruction　of　unknown　3-D　object　is　of　great　importance　in　areas　of　machine　vision　and　visualization.　In　this　paper,　a　new　view　planning　approach　of　generating　3-D　model　is　automatically　proposed.　The　new　algorithm　incorporates　the　visual　region　of　laser-vision　system　with　the　limit　surface　of　unknown　model　and　selects　the　suitability　of　viewpoints　as　the　NBV　on　scanning　coverage.　The　limit　surface　is　modeled　by　means　of　the　known　data　obtained　from　initial　view.　Then　the　visibility　zone　of　the　next　view　is　determined.　And　the　position　that　can　obtain　maximum　limit　surface　area　in　the　visibility　zone　is　defined　as　the　next　best　view　position.　Experimental　results　show　that　the　method　is　effective　in　practical　implementation.