Abstract: Optimization of the determination conditions of total Avenanthramides in oats by acid dye colorimetry. With the tranilast as a control standard at 340 nm,the acid dye species,buffer solution and acid dye dosage were optimized,and the best detection conditions were determined. The results showed that the best detection conditions were as follows:The acid dye was bromine cresol purple,the buffer was sodium hydrogen phosphate and sodium hydroxide with pH5.4,and the amount of acid dye was 3 mL. The linear range of this method was 0.306~45.9 mg/L,and the regression equation was y=0.04837x+0.00822,R²=0.9994,and the average recovery rate was 94.22%,RSD=1.79%. The results showed that the method had good linear relationship,high accuracy,good repeatability and simple operation,which would provide reference and basis for the determination of total avenanthramides content in oat.