Abstract: A biomedical ion sensitive sensor for sensing an ion concentration of a biomedicine sample includes an insulation layer formed on a substrate having a source region and a drain region. A gate oxide layer formed on the surface of the source region, the drain region, and the insulation layer. A chemical membrane layer is formed on the gate oxide layer. A concave ion sensitive portion is formed at an area of the surface of the chemical membrane layer defined between the source region and the drain region, and a rough surface is further formed on the ion sensitive portion. The ion sensitive film is made of Si3N4, SiO2, Al2O3, Ta2O5, SnO2, ZrO2, or HfO2. A plurality of biomedical ion sensitive semiconductor sensors are communicated with reactant micro-fluid channels to form a biomedical ion sensitive semiconductor sensor array.