Abstarct: Isogeometric Analysis (IGA) as a early developed computational method tries to integrate CAD and CAE packages. In this manner, while improving the accuracy of model geometry and analysis, computational effort also reduces. In this thesis, by review of the nurbs baxsed IGA, elasoplastic analysis of 2D problems according to this approach is considered. In this way, elastoplastic formulation of 2D problems and numerical methods of solving them are reviewed. Then by considering nurbs basis functions, the method of solving 2D elstoplastic problems baxsed on this functions are presented. By the developed code in MATLAB to solve these problems as “Elasto-plastic IGA”, numerical solution of some beanchmark problems are obtaind and compared with the FEM or analytical ones. Results show appropriate accuracy of the method and developed software.