Drug delivery system (DDS) mainly includes two parts: drug and carrier. Microsphere which is made from suitable polymer materials is a new drug carrier with a more extensive application. This paper studies the preparation method of polysucrose microspheres and the feasibility of drug control-released carrier. Taking Span-80 as surfactant

epichlorohydrin as cross linker

aqueous solution of Ficoll-400 as water phase (W)

chlorobenzene as the oil phase (O)

the experiment has made a series of spherical polysucrose microspheres within 100um particle size by adopting the method of inverse suspension polymerization. Taking bovine serum albumen ( BSA) as model drug

it studies the function of control-released when it is the drug carrier. Release experiment shows that the maximum release rate is 95% and appropriately increasing the degree of cross linking is helpful for BSA slow release.