Inhalation is the most important route of entry for aerosol particles. Further, it is necessary to determine the specific region of particle deposition for properly evaluating human health risk. The particle deposition in the respiratory system depends on the particle size, particle charge condition, particle density and breathing pattern. In the past decade, particle deposition in the respiratory tract is become popular research for drug delivery because of it is non-invasive and rapid absorption in medical care and industrial hygiene. Therefore, it is necessary to discuss how to measure the particle deposition in the respiratory tract in a rapid and efficient way. The aim of this study was to development and characterization of an aerosol bolus system for lung deposition measurement to, and (1) verify the availability of the system to compare to prior studies, (2) improve the efficiency of the system. Use of optical measurement could reduce particles loss due to unnecessary pumping, but it is worth noting that the laser intensity and stray- light background of the optical chamber. The aerosol bolus size was determined by the injection time and upstream pressure proportionally. The maximum of the bolus size would be set under the pressure 2.4 kPa and set injection time at 2.00 second, which output volume is approximately 90 ml; on the other hand, the minimum of the bolus size would be set under the pressure 1.2 kPa and set injection time at 0.03 second, which output volume is about 1.5 ml. When the injection time gets longer, the bolus would be more dispersed in the air under constant pressure, the half-width of bolus is 0.1 cm for Tinj 0.05 sec and 0.65 cm for Tinj 0.5 sec. The recovery rate of PMT will be more close to CPC on longer injection time. As the result, the injection time should be set at 0.08 second to avoid the bad resolution of the experiment. In the human test, the recovery rate is 5% difference between CPC and PMT; in addition, if exhaled to residual volume in the test, the recovery rate would be higher. This study recommended to development an real time on-line monitoring of respiratory therapy system by using the result of this experiment in the future.