In this study, a simple and cheap way to solve the drift problem is presented which describes the relation of drift and gate voltage. Constant various gate voltages are biased in sensing layers with reference electrode. It obviously shows a strong relation of gate drifts and gate stress voltages. When the gate voltage is controlled as 0.5 V, the drift voltage of SiO
gate ISFET will decrease from 56.12 to 2.94 mV in ten hours measurement. The improvement of drift voltage reaches 94.8%. When the gate voltage is controlled as -1 V, the drift voltage of ZrO
gate ISFET will also decrease from - 57.94 to 0.76 mV. The improvement of drift voltage reaches 98.7%. This may result from the gate electric field affecting the ions to diffusive into the gate insulator. By this way, we can commercialize the ISFET with a very low drift rate in a simple way.