Abstract: Aim ：To prepare bupropion hydrochloride(BH) 24-hour sustained-release pellets and to determine its oral bioavailability in rats. Methods ：BH 24-hour sustained-release pellets were prepared through the method of extrusion-spheronization and then were coated by ethyl cellulose-based aqueous disperse system using Mini-Glatt.And BH plasma concentrations in rats receiving administration of BH pellets or commercially available BH tablets were determined by HPLC.The pharmacokinetic parameters were estimated by Kinetica software. Results ：The cumulative release percents of BH sustained-release pellets in 2，12 and 24 h were 10%，80% and 95%，respectively.The plasma concentration-time curves of BH sustained-release pellets and BH tablets in rats after oral administration were fitted to two-and one-compartment models，respectively.AUCs of BH sustained-release pellets and BH tablets were found to be (1 523.79±323.30) ng ·h/mL and(1 379.67±253.61) ng ·h/mL，respectively；c_maxs were(163.80±32.93) ng/mL and(451.91±144.54) ng/mL，respectively；and t_maxs were(4.67±0.52) h and(0.5±0) h respectively.The relative bioavailability of BH sustained-release pellets to commercial BH tablets was (110.46±17.07) %. Conclusion ：The prepared BH 24-hour sustained-release pellets are bioequivalent to the commercial BH tablets.