Aiming　at　the　triangular　mesh　holes　generated　from　incomplete　point　cloud　data　in　reverse　engineering,　a　new　hole　filling　algorithm　in　space　was　presented.　The　holes　boundary　were　extracted　and　pretreated,　and　the　characteristic　plane　of　the　hole　boundary　was　established,　on　which　boundary　was　projected.　The　smallest　angle　between　the　projection　polygon　was　found　out　to　determine　the　corresponding　boundary　point　as　the　growing　point　for　hole　filling.　Hole　filling　moved　in　circle　until　the　original　hole　was　covered　by　the　new　triangular　meshes.　The　mesh　points　of　the　hole　boundary　were　chosen　as　the　sampling　points,　and　the　new　filled　hole　mesh　points　position　were　adjusted　by　least　squares　fitting　to　fill　the　hole　precisely.　Examples　proved　that　this　method　had　good　accuracy　and　stability　in　hole　filling.