Objective:To establish a method for the content determination of lactic acid in the haemodialysis.Methods:HPLC analysis was carried out with phenomenex Rezex ROA-Organic Acid(300mm×7.8mm,8μm)and 0.015mol/L sulfuric acid solution as the mobile phase.The detection wavelength was 220nm.Results:There was a good linear relationship between the concentration of lactic acid and the areas in the range of 0.18-0.72mg/mL(r2=1).The average recovery was 100.4%with RSD=0.46%(n=9).Conclusion:The method is simple,accurate and reproducible.It can be used as the quality control for lactic acid in the haemodialysis.