The development of strained-Si physical compact threshold voltage model is based on Poisson's equation, using the gradual channel approximation (GCA) and coherent quasi-two-dimensional (2D) analysis, as well as taking into account the effects of short channel effect (SCE), narrow channel effect (NCE), non-uniform doping effect, and drain-induced barrier lowering (DIBL) effect. Moreover, the threshold voltage parameters are extracted from the experimental results by software. Finally, the validity of our model is derived from the comparison of our simulation results. The proposed model may be useful for the design and simulation of very large scale integrated circuits (VLSI) made of strained-Si.