Unified Power Flow Controller (UPFC) is the most widely used FACTS device to control the power flow and to optimize the system stability in the transmission line. The controller used in the control mechanism has an important effect on the performance of UPFC According to this, the performance of UPFC for several case studies was observed by using different control mechanisms based on Proportional-Integral (PI) and fuzzy controllers in this study. Fuzzy Logic Controller (FLU) was developed by using Takagi-Sugeno inference system and used in UPFC. The case studies are applied to prove the capability of UPFC on power flow and the effectiveness of controllers on the performance of UPFC at the different operating conditions. PSCAD/EMTDC program is used to model UPFC and to verify the performance of UPFC with different controllers in the transmission line.