Abstract: This paper presents the fabrication of lowdensity silicon dioxide aerogel microspheres and the sol-gel transition process. The work covers the effects of suspension spheres, the density-match and aging time on the properties of resultant aerogel spheres, focusing on the shrinkage effects. Four different density microspheres are studied with expected density of 70mg/cm3, 100mg/cm3, 150mg/cm3 and 200mg/cm3 respectively. The results show that we can obtain microspheres with diameter from 0.1mm up to 2mm, and density in the range of 50~500mg/cm3,and the parameter of out of round is 1.8%．