A　novel　method　for　evaluation　of　the　roundness　error　based　on　curvature　is　presented.　The　condition　for　choosing　points　is　derived　from　the　definition　of　the　curvature　in　evaluating　the　roundness　error　with　maximum　inscribed　circle　or　minimum　circumscribed　circle.　The　points　with　the　least　radius　of　curvature　are　eliminated　with　maximum　inscribed　circle,　whereas　the　points　with　the　largest　radius　of　curvature　are　eliminated　with　minimum　circumscribed　circle.　According　to　the　above　condition　three　points　satisfying　with　the　criterion　for　evaluation　of　the　roundness　error　are　discovered,　so　the　roundness　error　is　determined.　The　points　are　divided　into　outer　points　and　inter　points　according　to　the　least　square　mean　circle　in　order　to　reduce　the　amount　of　computation.　The　points　are　eliminated　from　internal　points　for　maximum　inscribed　circle,　but　for　minimum　circumscribed　the　points　are　chosen　from　external　points.　The　correctness　and　the　feasibility　of　the　method　are　proved　through　an　example.