OBJECTIVE To establish an external standard HPLC method for the determination of metronidazole and chlorhexidine in two compound preparations. METHODS The Waters C₁₈column was used.The mobile phase was consisted of methanol water triethylamine(56:44: 0.1)(adjusted to pH of 3.0 by 50% phosphoric acid).The UV detection wavelength was 295 nm. RESULTS The two components had good resolution.The linear ranges were 10～29 μg·mL^-1for metronidazole and 41～124μg·mL^-1for chlorhexidine acetate with the correlation coefficients 0.999 8 and 0.999 9,respectively.The average recoveries were 99.59% and 99.5% with RSD less than 0.9%.(n=3). CONCLUSION This method was simple and accurate,and suitable for the determination of two components in compound preparation.