OBJECTIVE： To prepare Diacerein （DCR）-loaded （poly lactic-co-glycolic acid） PLGA microspheres for intra-articular injection and investigate its related properties. METHODS： PLGA was used as microspheres material， and the microsphere was prepared by emulsification solvent evaporation method. The contents of DCR-PLGA microspheres were determined by HPLC， and drug-loading amount and entrapment efficiency were also calculated. Using entrapment efficiency as evaluation index， the preparation technology was optimized by orthogonal test. The morphology and particle size of microspheres were observed by optical microscope and SEM. Accumulative release rate was investigated by using in vitro release test. RESULTS： The linear range of DCR was 2.1-105.0 μg/mL （r＝0.999 9）. RSDs of precision， stability， reproducibility and recovery tests were all lower than 2.0％. The optimal technology was PLGA concentration of 200 mg/mL， volume ratio of oil-water 1 ∶ 50， polyvinyl alcohol concentration of 1％. The prepared DCR-PLGA microspheres were spherical， average particle size was （11.2±4.7）μm， drug-loading amount was（4.25±0.26）％ and encapsulation rate was（92.30±1.93）％， respectively. The drug release rate of DCR-PLGA microspheres within 360 h was about（73.08±5.33）％. CONCLUSIONS： DCR-PLGA microspheres are prepared successfully with good morphology， suitable particle size and obvious sustained release effect， which are suitable for intra-articular injection.