The invention relates to a composition of cefazedone sodium sterile and clavulanate potassium and a proportion thereof. The composition is characterized by consisting of cefazedone sodium sterile and clavulanate potassium in a weight ratio of 1:1-8:1. In infectious diseases caused by bacteria, certain bacteria generate beta-lactamase which has medicament resistance to cefazedone, so the treatmentis not effective. After the cefazedone sodium sterile and the clavulanate potassium are applied in combination, different proportions of the composition have different and relatively strong antibacterial activities to gram negative bacilli and gram positive coccus which generates beta-lactamase. Tests show that the composition is sensitive to the bacteria strain generating beta-lactamase, so thatthe antibiotic action of the cefazedone sodium sterile can be increased by times and the enzyme-generating strain is restored to be sensitive to the cefazedone sodium sterile. The test bases are enough; the clinical antibacterial effect is clear; and the happening of adverse reactions is not increased.