Objective A method of ultra performance liquid chromatography-mass spectrometry （UPLC-MS） was established for the determination of octylphenol ethoxylates （OPEO） and nonylphenol ethoxylates （NPEO） in coating agent.Methods Samples were extracted with water， and purified by solid phase extraction column. And Thermo Acclaim RSLC 120 C₁₈ （2.1 mm×100 mm， 2.2 μm） chromatographic column was used for separation. Acetonitrile and 0.1% formic acid water were mobile phase， gradient elution and quantification was performed in SIM mode with positive ion mode of electrospray ionization.Results Octylphenol ethoxylates （OPEO） and nonylphenol ethoxylates （NPEO） were in the range of 0-400 μg/L， and the linear relationships was good （r²>0.996）. The recoveries at three spiked levels （0.12， 0.24 mg/kg， 1.2 mg/kg） were 88.5%-96.9% with the relative standard deviation of 2.9%-7.0%， and the limits of quantitative was 0.12 mg/kg.Conclusion The method was simple， rapid and accurate. Its sensitivity， accuracy and precision were suitable for the quantitative analysis and determination of alkylphenol ethoxylates in coating agent.