Abstarct: Magnetotellurics (MT) is a natural source electromagnetic method that is used in exploration of deep subsurface structures such as deep hydrocarbon bearing structures. The correct delineation of subsurface structures of each area using MT data necessitate an appropriate modelling method to be selected. The main purpose of this study is two-dimensional (2D) modelling of Gachsaran MT data using Non-Linear Conjugate Gradient (NLCG) smooth inversion and Sharp Boundary Inversion (SBI) techniques. These methods of inversion is implemented to identify the subsurface structures of this area including Sarab and Jafarabad anticlines properly, to delineate the upper boundary of Asmari formation precisely, to compare the results of these different inversion methods with together, and finally the obtained results are verified by all available geological and drilling data. To achieve the goals, the dimensionality analysis of subsurface structures is done at the first step, the effects of near surface inhomogeneities on MT data are then identified and corrected by TEM sounding data and finally the corrected MT data are modelled by 2D smooth and sharp boundary inversion approaches. The results of this study show that deep structures are mostly two and sometimes three-dimensional and it has been found that the modelling of TM mode data provide better results than the other modes of MT data. The obtained results also indicate that between two smooth and sharp boundary inversion techniques, the sharp boundary inversion provides better results which are in good agreement with drilling and geological information. The sharp boundary inversion has identified Aghajary, Mishan, Gachsaran and upper boundary of Asmari formation precisely. In addition, the large fault in the end of 8807 to 8810 profiles (Pishani Koohestan fault) and small and deep thrust faults in Gachsaran thick formation, were detected. Jafarabad and Sarab anticlines in 8807 profile, at the elevation of 1500m above sea level were also identified while in 8808 to 8810 profiles, Sarab anticline has been smoothed and only the anticline of Jafarabad is seen at an elevation of 1,000 to 1,500 meters. These results accord properly with those provided by drilling and geological data.