A rapid analytical method using on-line immunoaffinity column clean-up and high performance liquid chromatography(HPLC) was developed for the determination of aflatoxins(B1，B2，G1，G2) in feed samples.The samples were extracted with acetonitrile-water solution(80∶20,by volumn).The extraction solution was diluted by 10 times using 3 g/L triton X-100 water solution,then injected into the RIDA-CREST on-line immunoaffinity column clean-up system,and washed out with methanol-water(45∶55,by volume) as mobile phase at a flow rate of 1.0 mL/min.Aflatoxins were analyzed by HPLC/FLD with post-column photochemical derivatizaton.The detection limits of AFB1,AFB2,AFG1 and AFG2 were 0.08,0.05,0.18,0.08 μg/kg,respectively.The linear ranges for AFB1,AFB2,AFG1 and AFG2 were 1-100,0.24-24,0.56-56,0.24-24 μg/kg,with their correlation coefficients(r2) of 0.999 4,0.999 7,0.999 8 and 0.999 8,respectively.The recoveries for four kinds of feed samples spiked with aflatoxins were in the range of 72.6%-103%,with relative standard deviations of 2.5%-4.9%.Each immunoaffinity colomn could be used for 60 samples cleanup,and the total running time for each HPLC analysis is 15 min,thus 70-80 samples could be detected per day.This method could satisfy the demands for rapid and accurate analysis of aflatoxin in feed.