A method for the rapid determination of oxytertracycline and doxycycline in plasma was established by mix mode solid phase extraction(SPE) and quaternized cellulose supported Au nanoparticles(QC-Au NPs) coated capillary electrophoresis.The QC-Au NPs were used to coat the capillary inner surface and inhibit the adsorption of analyte.The pH value of running buffer was also optimized.The result showed that the peak shape and resolution were improved，and the separation efficiency was also increased.The number of theoretical plates of oxytertracycline increased by 17.9 times as compared with that of inner bare capillary.The adsorption of oxytertracycline and doxycycline was inhibited in the capillary coated with QC-Au NPs,and their analysis could be completed in 4 min.Good linearities were obtained for oxytertracycline and doxycycline in the range of 10-200 μg/mL，with correlation coefficients of 0.997 6 and 0.995 2，respectively.The recoveries of the analytes in plasma at three spiked levels ranged from 88% to 107%，and the relative standard deviations(RSDs) ranged from 1.4%-7.7%.This method is rapid，simple and accurate，and is feasible for the determination of oxytertracycline and doxycycline in plasma samples.