Objective：This study was designed to examine the interaction of cefminox sodium（CMNS）with bovine serum albumin（BSA）under the optimum conditions. Methods：The mechanism of the interaction between CMNS and BSA was studied by spectroscopic techniques combination with absorption spectroscopy. Results：Stern-Volmer analysis of fluorescence quenching data showed the presence of the static quenching mechanism. The thermodynamic parameters indicated that the electrostatic interactions were the predominant intermolecular forces stabilizing the complex. The number of binding sites（n）and binding constant（Kb）was calculated. The binding process was spontaneous. The obtained data for binding sites of n approximately equal to 1 indicated that there was a single class of binding site for the BSA with CMNS. The primary binding site for CMNS was located at sub-domain ⅡA of BSA and nearby tyrosine residue. The conjugation reaction would affect the conformation of BSA，leading to the polarity around BSA strengthened. Conclusion：There was almost some negative cooperative effect between CMNS and BSA. The obtained results provided references for its clinical application.