Abstract: The simulation of DopingLess TFET (DLTFET) is carried out. By research on characteristic parameter of conventional DLTFETs (Co-DLTFET), such as the carrier distribution, current density, potential distribution, and band diagram, the operational principle of this kind of transistors can be comprehensively and systematically understood. Based on the simulation study of DGTFET, a novel design of HG-TMDG-DLTFET is proposed, which is composed of two kinds of work function gate dielectric with tunneling gate (Ф_TG = 4.0 eV)-control gate (Ф_CG= 4.6 eV)-auxiliary gate (Ф_AG = 4.0 eV) and heterogeneous gate dielectric. The dual-gate undoped tunneling field-effect transistor (Hetero gate oxide TMDG-DLTFET, HG-TMDG-DLTFET), which contains a heterogeneous gate dielectric and three gate dielectric, can effectively promote the formation of steeper " abrupt junction ". The simulation results show that the effective tunneling area of the device is larger than that of the traditional DLTFET, the tunneling current is increased, and the frequency characteristics are very good. When the gate voltage is 1.0 V and drain voltage is 0.5V, the on-state current of HG-TMDG-DLTFET (I_on = 5.5×10⁻⁶ A) is 4 magnitude greater than that of Co-DLTFET (I_on = 5.9×10⁻¹⁰ A). And when the gate voltage further increase to 1.5 V, the current of this novel device can reach 2.3×10⁻⁵ A.