OBJECTIVE： To prepare Cefprozil bitter-masked pellets， and optimize its pellet core. METHODS： Pellet core of cefprozil were prepared by powder layering with centrifugal granulation， using adhesive concentration， guniting rotation speed and supplying powder speed as factors， comprehensive score of particle size distribution， yield， friability， repose angle and plane critical angle as indexes， the orthogonal test was used to optimize the formulation and technology of pellet core of cefprozil. Then the bitter of pellet core was masked by coating with talcum powder， polyacrylic acid resin and orange essence. The texture and accumulative dissolution rate was evaluated. RESULTS： The optimal formulation and technology of pellet core of cefprozil were adhesive concentration of 3％， guniting rotation speed of 15 r/min and supplying powder speed of 30 r/min. The prepared pellet core of cefprozil with 40-50 meshes were particle size of 94.0％， yield of （92.1±2.9）％， friability of （1.1±0.1）％， angle of repose of （23.2±0.4） °， plane critical angle of （6.5±0.4） °（n＝3）. After coating， Cefprozil bitter-masked pellets were bitterless， and accumulative dissolution rate of cefprozil was more than 85％ within 45 min. CONCLUSIONS： Cefprozil bitter-masked pellets are prepared successfully， and the optimized formulation of pellet core of cefprozil are rational.