Abstract: A method based on capillary electrophoresis with ultraviolet detection was developed for simultaneous determination of tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) and chloramphenicol (CAP) residues in seafood. The effects of some important factors such as additive, acidity and concentration of running buffer,separation voltage, injection time and temperature were investigated to acquire the optimum condition. In 278 nm wavelength, the five analytes could be well separated within 25 min on a 65 cm length capillary at the separation voltage of 22 kV in 20 mmol/L Na₂HPO₄-10 mmol/L citric acid (pH 2.8) with additive of 0.25 mmol/L Na₂EDTA and volume ratio is 4.0% Tween-80. The calibration curves of TC、CTC、OTC、DC and CAP were linear by plotting the peak aera against the sample concentration over the range from 2.5 mg/L to 300.0 mg/L and 10.0 mg/L to 300.0 mg/L. The correlation coefficiency were 0.999 6, 0.999 2, 0.999 3, 0.998 4, 0.998 7 for TC、CTC、OTC、DC and CAP, respectively. The detection limits were 0.5 μg/mL for TC, 0.5 μg/mL for CTC, 0.5 μg/mL for OTC,1.5 μg/mL for DC and 1.0 μg/mL for CAP(S/n=3). This method also could be applied to analyze the other kinds of samples for the residues of the five antibiotics.