The channel region of seep-sub-micrometer MOSFET is non-uniformly doped with pocket implant. Therefore, the advanced threshold voltage model is needed to account for the Short-Channel Effect and Reverse-Short-Channel Effect due to the non-uniform doping concentration in the channel region. In this paper, A scalable analytical model for the MOSFET threshold voltage is developed. The developed model is verified with MEDICI and TSUPREM simulator.