Ion Sensitive Field Effect Transistors (ISFET) are most widely used in medical applications due to simple integration process, measurement of sensitivity and its dual properties. These ISFETs are originated from Metal Oxide Semiconductor Field Effect Transistors (MOSFET) with improvements in structure. ISFETs are used as bio-sensors for the detection of biomarkers in blood, DNA replication and several other medical applications. In this article, we design the ISFET pH sensor in two dimensions with integration of two models namely, semiconductor model and electrolyte model are represented using manageable global equations. The sensitivity of ISFET with different oxide layers is measured and compared. We also measure the sensitivity of the designed 2D-ISFET in two different solutions and compare it with different oxides to know the best oxide material to be used to design the device.