This paper presents a novel physics-based analytical compact model for the drift region of a high-voltage metal-oxide-semiconductor field-effect transistor (HV-MOSFET). According to this model, the drift region is considered as a simple 1-D problem, just as that of a low-voltage inner MOS transistor. It exploits the charge-sheet approximation and performs linearization between the charge in the drift region and the surface potential. The drift region model combined with the standard charge-sheet MOS model for the low-voltage part adds up to a complete HV-MOSFET model, which is verified against technology computer-aided design simulations and measurements of HV-MOS transistors. The comparisons demonstrate its accurate physics foundations and underline that this novel approach to the modeling of the drift region of the HV-MOSFET is promising.