A cylinder shape photoacoustic (PA) cell has been designed and fabricated for midinfrared laser photoacoustic spectroscopy (MIRPAS) gas sensing application. A complete modeling of the acoustic signal transmission and detection in the PA cell using FEM have been performed to simulate its characteristics and compared systemtically with the measured data. Results show that the second longitudinal mode of the PA cell has the highest resonance amplitude around 4.2 KHz with moderate Q value, so this mode is quite suitable for MIRPAS gas sensing purpose.