Abstract: Both starch and PVA have good biocompatibility and biodegradability,and have been widely used in the field of medicine.As a kind of new functional polymer microspheres material,starch microspheres are the good carrier for the delivery of hydrophilic drugs.The composite microspheres prepared by some materials with good compatibility with starch (such as PVA etc.) have more advantages than single material.In the present study,starch/PVA microspheres were prepared by reverse phase emulsion polymerization method with soluble starch and polyvinyl alcohol (PVA) as raw materials and epichlorohydrin (EPI) as crosslinked agent.The effect of temperature,raw material dosage,rotational speed and other factors.on the particle size distribution of starch/PVA microspheres was discussed.The morphology and structure of microspheres were characterized via scanning electron microscopy,X-ray diffractometer (XRD),Fourier transform infrared spectroscopy and laser particle size analyzer.The results showed that the optimal conditions for starch/PVA microspheres preparation were as follows:starch dosages of 5 g,PVA of 0.05 g,oil to water ratio of 3:1(V/V),emulsifier dosage of 1.5 g,reaction temperature of 65℃,stirring rate of 700 r/min,EPI dosage of 5 mL and the reaction time of 1.5 h.Under the above optimum conditions,the average particle size of the prepared microspheres was 16.464 μm,and the afforded products had smooth and uniform appearance,pore structure and lower crystallization ability.