OBJECTIVE： To establish a method for simultaneous determination of residual methylparaben， ethylparaben， nipasol and benzalkonium chloride in marketed eye drops. METHODS： HPLC method was adopted. The determination was performed on Hypersil GOLD C18 column with mobile phase consisted of 0.005 mol/L ammonium acetate （10 mL triehtylamine in 1 L solution， pH adjusted to 5.0±0.5 with glacial acetic acid）-acetonitrile （45 ∶ 55，V/V） at the flow rate of 1.0 mL/min. The detection wavelength was 262 nm （methylparaben， ethylparaben， nipasol） and 214 nm （benzalkonium chloride）， respectively. The column temperature was 30 ℃ and sample size was 20 μL. RESULTS： The linear range were 1.235 0-15.438 0 μg/mL for methylparaben（r＝0.999 9）， 1.317 0-16.383 6 μg/mL for ethylparaben （r＝0.999 7）， 1.207 2-15.089 4 μg/mL for nipasol （r＝0.999 6） and 17.776-222.0 μg/mL for benzalkonium chloride （r＝0.999 9）， respectively. Limits of quantitation were 2.0， 2.0， 2.0， 1.11 μg， respectively； limits of determination were 0.375， 0.375， 0.375， 0.333 μg， respectively. RSDs of precision， stability and reproducibility tests were all lower than 2.0％. The average recoveries were 98.14％-102.48％ （RSD＝1.6％，n＝9）， 98.79％-102.42％（RSD＝1.3％， n＝9）， 98.19％-102.49％（RSD＝1.5％，n＝9） and 98.76％-100.53％ （RSD＝0.6％，n＝9）， respectively. CONCLUSIONS： The method is accurate， reproducible， simple and suitable for the determination of residual methylparaben， ethylparaben， nipasol and benzalkonium chloride in marketed eye drops.