Dispersion copolymerization of styrene (St) and divinylhenzene (DVB) was carried out in mixture solvents composed of ethanol (EOH) and ethylene glycol monomethyl ether (EGME) using hydroxypropylcellulose (HPC) as a steric stabilizer．Monodispersed crosslinked polystyrene microspheres were prepared in an average diameter range of 6～10 μm．The effects of the amount of styrene

divinylbenzene

initiator AIBN and ratio of EOH／EGME on the average size and size distribution of microspheres

and on the variation of particle number and polymerization rate were studied．With increasing styrene and initiator AIBN

the polymerization rate and the particle size increase

but the size distribution broadens

at the same time the particle number first increases

and then decreases．The particle size increases

and the size distribution becomes narrow with increasing the ratio of EOH/EGME．The concentration of stabilizer has no obvious effect on the polymerization rate and size distribution of particles

but the average size of particles decreases and the particle number increases with increasing the stabilizer concentration．The effects of the post-addition method on the average size of particles and size distribution were also discussed.