In this work, a double gate junction-less tunnel FET (DG-JLTFET) has been evaluated for biosensing applications. Tunnelling is the concept in JLTFET which is a heavily doped JL transistor, by decreasing the barrier length between the source and channel of the device which is easily used for switching (ON and OFF) purpose. Based on the research and simulation so far on JLTFET, this has achieved a greater performance when compared to that of MOSFET. JLTFET with more dielectric (k) and low K spacers will give an ON current (0.1 mA/µm) for gate voltage 3V and for off current of (10−15 A/ µm) and performance with Ion/Ioff ratio at 1012 and subthreshold swing with 60 mV/dec is obtained at 20 nm length of the gate at room temperature. So, JLTFET is a better device for switching performance. The evaluation of device performance is also done based on different cavity thicknesses and different dielectric constants. Including these parameters, double gate-pocket-junction-less TFET is highly used in biosensor applications. In the following, we demonstrate high performance based on pocket region which is introduced to implement in JLTFET for biosensor label-free detection