Abstract: OBJECTIVE To optimize the preparation technique of gastric floating tablets of sodium ferulate and study the release mechanism of diammonium glycyrrhizinate release from the tablet. METHODS The gastric floating tablets were prepared with HPMC K4M as gel-matrix, cetyl alcohol as floating-assistant, NaHCO3 as gas-producer. The formulation was optimized by central composite design-response surface methodology. Release mechanism of diammonium glycyrrhizinate from gastric floating tablets was established by equation fitting. RESULTS Optimized formulation region of gastric floating tablets were found. The initial floating time was less than 1 min and the durative floating time was more than 10 h. CONCLUSION Central composite design were successful in optimizing the preparation of tablets with accurate and gastric floating tablets had good floating and sustained release ability.