A new method for the determination of acetaminophen was established by flow injection technique as CeO2 nanoparticles(CeO2 NPS) could effectively enhance the chemiluminescent(CL) intensity of luminol-KMnO4 system in alkaline conditions.In this study,a variety of factors influencing the chemiluminescence detection signal were studied,while the possible CL mechanism was discussed.Under the optimum experimental conditions,the concentration of acetaminophen was linear with the inhibition of relative CL intensity in the range of 1.0×10-7 mol/L-5.0×10-5 mol/L.The detection limit(3σ) was 3.3×10-8 mol/L.And the relative standard deviations(RSD) were calculated to be 0.3% for 11 times parallel detection on 5.0×10-6mol/L acetaminophen solution.The method was successfully applied in the determination of acetaminophen in Yinqiao tablets and urine with the satisfactory recoveries of 98.0% and 97.9%-98.7%,respectively.