In this paper, we put emphasis on the study of the temperature effect of the ISFET (ion sensitive field effect transistor) based on the hydrogenated amorphous silicon (a-Si:H). Since the temperature influences the properties of the ISFET device, we studied the influence of the temperature effect to ISFET in detail. In this paper, we prepared the a-Si:H/SiO2/p-Si/Al structure of ISFET devices by plasma-enhanced chemical vapor deposition (PECVD). The thickness of the a-Si:H was 2000 Angstrom. Then we used epoxy to encapsulate the a-Si:H pH-ISFET device. Furthermore, we utilized Keithley 236 Semiconductor Parameter Analyzer to measure the I-V curve, and then pH sensitivity of the a-Si:H pH-ISFET was determined. Since the a-Si:H thin film is easily dissolved in alkaline solution, so it was measured in acid solutions between pH 1-7. The experimental results were also compared with the simulated results. We can conclude that the experimental results approximately agree with simulation results.