Abstract: For the optimization of the detective methods of the fatty acid in goose fatty liver and goose liver catsup, the best method of disposal sample was achived through five different disposed methods for fatty acid methyl esterification. This method is hydrochloric acid-methyl esterification. Firstly the fat is distilled from sample by 15 mL chloroform and methanol (2∶1(v/v)), then saponificate with 15 mL 1 mol/L potassium hydroxide-ethanol. At last the sample of methyl esterification is obtained through plusing 30 mL 4％ hydrochloric acid-methanol into saponificative solution to methyl esterification. The results approve that the method is the best.