Objective: To investigate the content of ethylparaben in potassium chloride solution.Methods: According to the guidance for antibacterial effect test stated in Chinese Pharmacopoeia(the 4th volume of 2015 edition), 5 standard bacterial strains including Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa,Candida albicans and Aspergillus niger were used as the challenging strains.Using the logarithm decrease of bacteria number as the index, the antimicrobial effectiveness of ethylparaben at different concentrations was studied to screen out the optimal concentration in the solution.Results: The growth of the 5 standard bacterial strains was inhibited effectively by potassium chloride solution containing 0.05% ethylparaben, which was also the minimum effective concentration.Conclusion: 0.05% Ethylparaben is suitable as the bacteriostatic agent for potassium chloride solution.