To prepare gastric floating sustained-release tablets of Chinese herbal compound Zuo jin and Yuanhuzhitong and evaluate its release characteristics in vitro. Methods:The sustained-release tablets were prepared with hydroxypropyl methyl cellulose (HPMC) as hydrophilic gel-matrix and sodium bicarbonate as the foaming agent. The best formulation and preparation routes of the tablets were optimized by orthogonal experiment design using floating capability and release profile in vitro as indicators. Results:The investigation showed that the floating sustained-release tablets could quickly emerge on the artificial gastric fluid surface and maintained a sustained floating state for over 10 hours in vitro. The sustained-release property was good in vitro and the release profiles kept well with the equation of Peppas. Conclusion: The optimized tablets possess quick floating and ideal sustained-release characteristics in vitro.