Based on T/C ratio,a colloid gold immunochromatographic assay was developed for rapid and quantitative detection of clenbuterol residues in pork.The linear range of the new quantitative method was from 0.1 to 1.5 ng/g with a detection limit at 0.19 ng/g.Five pretreatment methods were compared.The result showed the best condition was 0.02 mol/L HCl containing 2.8% NaCl as the extracting solvent,extracting twice.The average recovery was 76.7% with a coefficient of variation 7.4%.For real sample spiked experiments,the results showed that the average recoveries were 60.4±12.8%,70.24±4.2%,75.9±4.9% and 71.1±5.0% with CLE concentrations of 0.5,1,2 and 3 ng/g,respectively.The new quantitative system had a high coefficient of correlation with traditional ELISA(R2=0.9136).These results demonstrated that T/C ratio based colloidal gold test strip is a sensitive,reproducible method for on-site detection of CLE in pork samples.