Abstract: OBJECTIVE To investigate in vitro dissolution behavior and its influencing factors of montelukast sodium chewable tablets, to provide reference for the development of new dosage forms and consistency evaluation of generic drugs. METHODS The effects of pH, bile salts, surfactants and other factors on the dissolution of sodium chewable tablets were investigated. RESULTS In the medium with pH 7.5, the solubility of montelukast sodium increased significantly with the increase of bile salt concentration. The dissolution of montelukast sodium chewable tablets in pH 1.0 hydrochloric acid solution, pH 4.0 acetate solution and pH 6.8 phosphate solution rapidly precipitated to form a suspension, while 0.5% SDS aqueous solution inhibited its precipitation. CONCLUSION The dissolution of montelukast sodium chewable tablets is greatly affected by pH, bile salts and surfactant. It will be the reference and experience of formulation and quality consistency evaluation for generic drugs in future.