A 2-D analytical model for the surface potential and threshold voltage in fully depleted dual-material gate(DMG) SOI MOSFETs with high-k dielectric is developed to investigate the short-channel effects(SCEs). Our model takes into account the effects of the length of the gate metals and their work functions, the applied drain biase,and the gate dielectric constant. We demonstrate that the surface potential in the channel region exhibits a stepped potential variation by the gate near the drain, resulting in suppressed SCEs. With dielectric constants increasing, this novel device shows inverse SCEs. The derived analytical models are in good agreement with the resafts of the two-dimensional device simulator ISE.