Using styrene as raw material, potassium persulfate as an initiator, beta-cyclodextrin as a stabilizer, polystyrene microspheres were successfully prepared with nice monodisperse feature by means of soap-free emulsion polymerization method. Experimental studies were performed in detail to check the effect of the synthesis process of the microspheres, the stabilizer dosage, monomer concentration, and initiator dosage on the particle size and distribution, the microstructures were characterized with SEM, TEM, infrared (IR) and the particle size distribution investigation. The results show that the appropriate changes in amount of stabilizer and monomer concentration and dosage of initiator can result in a different particle size and polystyrene microspheres with good monodispersity were finally obtained.