Subthreshold conduction is governed by the potential distribution. We focus on full two-dimensional(2D) analytical modeling in order to evaluate the 2D potential profile within the active area of Fin FET structure.Surfaces and interfaces, which are key nanowire elements, are carefully studied. Different structures have different boundary conditions, and therefore different effects on the potential distributions. A range of models in Fin FET are reviewed in this paper. Parabolic approximation and evanescent mode are two different basic math methods to simplify the Poisson’s equation. Both superposition method and parabolic approximation are widely used in heavily doped devices. It is helpful to learn performances of MOSFETs with different structures. These two methods achieved improvement to face different structures from heavily doped devices or lightly doped devices to junctionless transistors. We focus on full two-dimensional (2D) analytical modeling in order to evaluate the 2D potential profile within the active area of ​​Fin FET structure. Surfaces and interfaces, which are key nanowire elements, are carefully studied. Different structures have different boundary conditions, and therefore different effects on the potential distributions. A range of models in Fin FETs are reviewed in this paper. Parabolic approximation and evanescent mode are two different basic math methods to simplify the Poisson’s equation. Both superposition method and parabolic approximation are widely used in heavily doped devices. These two methods achieved improvement to face different structures from heavily doped devices or lightly doped devices to junctionless transistors.