Using tetraethyl orthosilicate （TEOS） as silicon source and N，N-dimethylformamide (DMF) as emulsified porogen, partially condensed poly(ethoxy)siloxane (PES) was obtained by acid-catalyzed method. PES was further catalyzed by alkali to obtain mesoporous silicon dioxide microspheres. The effects of the amount of acid catalyst, spin temperature on the viscosity and degree of polymerisation of PES and the effect of PES viscosity on the particle size of silicon dioxide microspheres were investigated. The effects of the amount of ammonia water, the type of emulsified porogen, the amount of emulsified porogen, the stirring speed and the post-treatment method on the properties of silicon dioxide microspheres were also studied. The microspheres were characterized by scanning electron microscopy, rotational viscometer, nitrogen blow adsorption and Fourier infrared spectroscopy. The results show that the prepared mesoporous silicon dioxide microspheres are spherically intact, with uniform particle size distribution and high purity. The average pore size of microspheres is 10.164 4 nm, the pore volume is 1.023 023 cm3/g and the specific surface area is 396.528 1 m2/g.