This paper investigates the threshold voltage analytic model of strained SiGe-on-insulator p-channel metal-oxide-semiconductor-field-effect-transistor (SGOI pMOSFET), revises the energy band model of strained-silicon, and extracts the main physical parameters of strained-SiGe devices. These parameters include the energy gap, electron affinity, build-up potential, etc. In this paper, the two-dimensional Possions equation of build-in potential in strained silicon SGOI pMOSFET is also presented. By using the boundary conditions to solve these equations, an accurate threshold voltage analytic model is proposed and its validity is verified.