In this paper, a rigidity theorem of hypersurface in real space form will be given. In addition, we obtain rigidity theorems of submanifold in sphere which improve the result of Hou and Xu.
The Frenet-Serret formula is used to characterize the constant angle ruled surfaces in R3. When the surfaces are the tangent developmental and normal surfaces, that is, r（s, v） = tr（s） ＋v（cosα（s） . t（s） ＋sina（s） . n（s））, it is shown that each of these surfaces is locally isometric to a piece of a plane or a certain special surface. When the surfaces are normal and binormal surfaces, that is, r （ s, v ） = σ （ s ） ＋ v （ cosa （ s ） . n（s） ＋ since（s） . b（s））, it is shown that each of these surfaces is locally isometric to a piece of a plane or a cylindrical surface.
