Coaxial electrospray is a method for producing core-shell particles. Different parameters such as operation, geometric, and environmental parameters are affecting on the Coaxial electrospray process. So far, rare research has been devoted to studying coaxial electrospraying with air as core fluid and a liquid as shell fluid, and its governing physics is not entirely recognized. The present research explores this process and the role of significant coaxial electrospray parameters with air as core fluid by high-speed imaging and image processing technique. Furthermore, some numerical simulations are conducted to investigate the effects of fluid physical properties on the process. In the experiments, the liquid flow rate, the airflow rate, and the applied voltage varied in a range of 60ml/hr-140 ml/hr, 7.74ml/hr-20.33ml/hr 12.2kV-15kV, respectively. It was shown that by increasing the liquid flow rate, the diameters of bubbles decrease. Also, increasing the applied voltage decreases the bubble diameters only at high liquid flow rates without any noticeable effects at the lower flow rates. Increasing the airflow rate leads to producing bubbles with a larger diameter. However, this behavior is also observed when the liquid flow rate is high enough, and in the low fluid flow rate, it mainly affects the bubble generation frequency. The other investigated parameters include the distance between the nozzle and the electrode, the electrode inner and outer diameters, and the inner and outer nozzles assembly respect to each other. It is observed that we could produce smaller bubbles in size by reducing the nozzle and electrode distance, increasing the outer electrode diameter, or decreasing its inner diameter. And, increasing the distance between nozzle outlets cause smaller bubbles generation. Moreover, in the numerical simulations, it was observed that when the liquid surface tension increases from 0.04 N/m to 0.09 N/m. An increase of 33% occurs in bubbles’ diameters (no changes were applied to other parameters). On the other hand, decreasing the viscosity from 0.11 mpa.s to 0.05 mpa.s leads to a 23% increase in the bubble diameter. The distance between nozzle outlets is the last parameter that was also studied via simulation. It was demonstrated that one of the reasons contributing to bubble diameter changes with the change of this parameter is the change in electrical forces on the bubble. Keywords: Coaxial electrospray-Microbubble-Hollow micoparticles.