The CaO-SiO₂-P₂O₅ bioglass (BG) microspheres with good bioactivity and osteoconductivity have been extensively studied for bone tissue engineering. Traditional melting method for preparing BG powders is high energy consumption, and difficult to control the morphology of BG. While Sol-Gel technique for BG preparation requires a large amount of organic solvent, long preparation period and low mass production. For the rapid and scalable preparation of BG microspheres with controllable morphology, particle size and chemical composition, an efficient strategy of spray drying of precursor solution was proposed in this study, and the effects of process parameters including inlet air volume, precursor solution concentration and feed rate on the particle size of BG microspheres, and the effect of chemical composition on the apatite formation ability of BG microspheres in vitro were investigated. The results showed that the particle sizes of BG microspheres via spray drying could be controlled below 40 μm, and the particle sizes of BG microspheres increased with the concentration of precursor solution, and decreased with the increase of inlet air volume, but the feed rate has a slight effect on the particle size of the microspheres. On the other hand, BG microspheres with different chemical compositions had good ability to induce apatite formation in vitro, and it increased with the increase of CaO content. Therefore, spray drying method would be promising for rapid and scalable preparation of BG microspheres.