Abstract: With the rapid progress of high power laser technology in China, the specifications on the diameters of PS-PVA double-layer hollow microspheres used in inertial confinement fusion (ICF) physical experiments have increased to 700 m～900 m. In order to improve the yield of the double-layer hollow microspheres with 700 m～900 m diameter, both the surface modification on the PS microspheres by ozonizing and the optimization on the structure of impeller for stirring paddle were used to improve the traditional emulsion microencapsulation technique. The hydrophobic surface of the PS microsphere showed hydrophilic properties after the ozonization modification, which enhanced the interaction between PS microspheres and PVA coatings. Moreover, the optimization on the structure of impeller for stirring paddle improved the uniformity of the liquid field in the container, resulting in the movement stability of the microspheres. The above modifications benefited improving the yield of the large-diameter double-layer hollow microspheres.