Abstract: Objective To discuss and determine the contents of oxalate、citrate and uric acid in urine at the same time by capillary electrophoresis.Methods Sample was separated and the three substances in urinary were determined in 60cm×75μm capillary and phosphate/borate buffer,additive electroomotic flow modifier at constant voltage of -15kV,constant temperature of 25℃ and 185nm wave length ultraviolet detector.Then quantitative linearity range,sensitivity,accuracy and detection limit were detected by negative pole injection and positive pole detection.Results The correlation coefficient was larger than 0.999,variation coefficient of peak time and peak area was smaller than 1%,4% in the concentration range of 110mg/L-50mg/L,1.0mg/L-100mg/L,1.0mg/L-200mg/L correspondingly oxalate,citrate and uric acid respectively.Conclusion The analysis method was high practical for its simplicity,rapidity,cheapness,automation and its accuracy and precision can meet the analysis requirements.