Combined shear extrusion (CSE) is a new severe plastic deformation (SPD) technique to produce bulk ultra-fine grained materials. CSE is obtained by the combination of simple and pure shear extrusion. This technique is based on definitions of pure and simple shear. In the present work, the nonlinear (large) deformation elasticity theory is used for obtaining the shear strain applied to the sample under pure shear extrusion with various angles of distortion. Also plastic deformation characteristics of CSE method were analyzed with finite element analysis using commercial Deform 3D software. Shear strain and effective strain applied to the sample, the load required to carry out the process and the final shape of the cross-sectional area were studied for different angles of distortion. Analytical results and finite element analysis shows by increasing the angles of distortion, shear strain and increased rate of shear strain applied to the sample increased so the effective strain and load required to carry out the process increases. Analysis of finite element and geometry of the die shows that distribution of shear strain and effective strain is inhomogeneously and symmetrical in specimen’s cross section which increases from the center to the corners and by increasing the angles of distortion, distribution of strain becomes more inhomogeneously, also the final shape of the cross-sectional area deforms more.