In this thesis, we develop an acute triangle mesh elements in arbitrary angles. Although we have a rectangular mesh analytical method, acute triangle mesh effectively to decrease the total amount of computation nodes. It can be applied to cylindrical coordinates for accurate and rapid simulation than the rectangular mesh simulations. For verification, a simple 2D resistor will be simulated and compared to the theoretical value. Finally, we simulate a gate-all-around MOS capacitor by acute triangle mesh. According to the result of MOS-C simulation, we discuss the dependence of threshold voltage on the radius and the oxide thickness.