A novel high-voltage Controllable SenseFET (C-SenseFET) by inserting the second gate and its conductance model is proposed in this letter. Compared with conventional incontrollable SenseFET, the new structure features a controllable sensing region “S-Region” and a stable charging region “C-Region.” While varying the second gate voltage, the conductance of the channel between the two gates G1 and G2 is altered and the controllability of the on-state current is realized. It is experimentally demonstrated that the values of conductance g are 100 and 87.5 μS under the second gate biases of 0 and –4 V (with the device width of 75 μm), respectively, which are in agreement with simulations. The charging swing factor of C-SenseFET is measured to be 0.16, only 11% of the conventional counterpart, accomplishing higher stability of charging process. Moreover, the breakdown voltage of C-SenseFET achieves 700 V which increases by 300 V compared with conventional SenseFETs due to the implementation of Double-RESURF.