Establishing　dynamic　trust　relation　is　the　beginning　of　interaction　and　cooperation　among　entities　under　large　scale　distributed　environment.　The　computing　of　t　Trustworthiness　in　current　trust　dynamic　level　scheduling　algorithm　is　a　little　rough,　and　they　only　research　the　scheduling　algorithms　which　apply　in　executing　sequence　tasks.　A　new　trust　dynamic　level　scheduling　algorithm　based　ontology　trust　model　is　presented.　It　improves　the　trust　computation　for　different　aspects　and　supports　executing　composite　tasks.　Simulation　experiments　prove　that　the　algorithm　can　assure　the　execution　of　composite　tasks　in　a　highly　successful　level　in　task　scheduling.