Abstract: Gentamicin sulfate sustained- release tablet remaining- floating in stomach (G- HBS) was developed based on the hydrodynamically balanced system. The dissolution rate of G-HBS was determined by rotary basket method(100 r/min, 37± 0.5℃, 0.1 mol/L HCl). The release characteristics of G- HBS showed basically first order kinetics with the dissolution rate constant (K_r) of 0. 3992 h^-1. The mean dissolution time (MDT) of G- HBS was 2.53 h^-1. The density of G- HBS was found to have no significant influence on dissolution of G- BHS. The γ- scintiphoto technique was used to examine the gastric retention time of G- HBS and GCT (gentamicin sulfate conventional tablet). It was shown that the gastric retention time of all subjects taking G- HBS under fed and fasted conditions were all over 4 h, in contrast with GCT, only 1～ 2 h. The stability of G-HBS was investigated and a tentative two-year expiration date was established. Spectrophotometry for the determination of gentamicin was established. The effect of G-HBS on Campylobacter pyloridis- associated chronic gastritis was examined through clinical trials.