Low-temperature polycrystalline silicon thin film transistors (poly-Si TFTs) have been studied because of their high performance in Active Matrix Liquid Crystal Displays (AMLCD's) and Active Matrix Organic Light-Emitting Diode (AMOLED) applications. The purpose of this work is to simulate the impact of varying the electrical and physical parameters (the interface states, active layer's thickness and BBT model) in the transfer characteristics of poly-Si TFT to extract the electrical parameters like the threshold voltage, the mobility and to evaluate the device performance. The device was simulated using ATLAS software from Silvaco, the results show that the electrical and physical parameters of poly-Si TFT affect significantly its transfer characteristics, choosing suitable parameters improve high-performance transistor. Such results make the designed structure a promising element for large-scale electronics applications.