The problem of modelling plasticity in materials has been investigated for the past 200 years. Standard theories on yielding for metals go back to the era of Tresca(1864) and von Mises(1913). The rapid rise of the finite element method and new testing techniques in the last few decades led to further research. This thesis aims to model large-deformation plasticity in metals using the Bai-Wierzbicki material plasticity model to account for local- ization and the effect of the stress state in the material. Further, a new element technology, the edge-based smoothed finite element method(ES-FEM), is used to increase the accuracy and convergence rate of the numerical solution. The scope of this thesis is limited to plane stress and plane strain plasticity but can be extended to 3D problems. This technique is implemented in ABAQUS using a user element(UEL) subroutine written in FORTRAN 95. The results show that the ES-FEM element performs more accurately than the traditional finite element for large-deformation plasticity problems.