OBJECTIVE： To prepare vancomycin-loaded chitosan sustained-release microspheres and to study its drug release  and antibacterial effects in vitro. METHODS： The emulsion cross-linking was used to prepare vancomycin-loaded chitosan sustained-release microspheres， and the particle size and morphology of microspheres were observed. The contents of vancomycin in microspheres was determined by UV spectrophotometry， and drug-loading amount of entrapment efficiency were calculated. Drug release of prepared microspheres and vancomycin hydrochloride within 24 h were compared by release trial in vitro， and then its accumulative release rate （Q） within 7 d was investigated. The effects of prepared microspheres on the diameter of inhibition zone to Staphylococcus aureus after treated for 20 d were observed through  in vitro antibacterial test.  RESULTS： The microspheres were spherical and complete round without obvious bump and pore. The average particle size of the microspheres was （165.6±19.7）      μm； average drug-loading amount was （32.6±3.2）％； average encapsulation efficiency was （53.8±6.3）％； Q7 d was 82.7％. Q2 h of prepared microspheres and vancomycin hydrochloride were 18.6％ and 91.3％. The diameter of inhibition zone was higher than 3 cm after treated for 1 d， and then decreased gradually as time. CONCLUSIONS： Vancomycin-loaded chitosan sustained-release microspheres can be prepared successfully， and show obvious in vitro sustained-release effect and antibacterial effects.