In this article, a semiempirical model for enhancement-mode (E-mode) AlGaN/gallium nitride (GaN) high-electron mobility transistors (HEMTs) with p-GaN gate is extended from Advanced SPICE Model (ASM). By incorporating a Schottky metal/p-GaN diode, this model captures the effects of the p-GaN layer on gate current, capacitance, and dynamic characteristics. Additionally, the mobility model is extended for multiple temperatures, the intrinsic gate is involved in the cross-coupling effect, and the modulation effect model is extended to V-ds -dependent. These extensions are still compatible with ASM, and the rms fitting errors are less than 5%. Furthermore, this model can capture the V-off drift phenomenon. And double-pulsed simulation is performed to demonstrate the convergence and effectiveness in practical applications.