Abstract: This paper studied the extraction of amino acids by acid hydrolysis method and composition analysis from castor bean meal. The influence factors, concentration of sulfuric acid, reflux time, solid to liquid ratio and estraction methods, which could affect the extracting amino acids were investigated. The experimental results showed that, the optimum technological conditions of extracted amino acid was that concentration of sulfuric acid was 4mol /L, solid to liquid ratio was 1 ∶6, reflux times was 6h and the extraction method was filtration. Under this condition, the amino acid extraction rate was 55.692%, the highest content of glutamate was 18.5%.