Abstract: L- amino acid oxidase,which catalyze the biosynthesis of keto acid and other chemicals from L- amino acid,is applied in many fields of industry. The LAAO from Rhodococcus opacus was cloned and heterologous expressed in Escherichia coli,followed the investigation of induced conditions and biosynthesis of 5- aminovaleric acid.The results showed that the optimum induction temperature of L- amino acid oxidase was 25 ℃,The optimal concentration of inducing agent,induction time,the cell mass were 0.5 mmol / L,7 h,0.246 g / L,respectively.Meanwhile,biocatalytic conditions were optimized to improve the production of 5- aminovaleric acid. The optimal substrate molar concentration of biosynthesis of 5- aminovaleric acid was 17 mmol / L,furthermore,the optimal p H,temperature,time,supplemented with H₂O₂,addition of the enzyme and FAD molar ratio were 7.0,37 ℃,24 h,0.5%,1∶1,respectively.As a result,a 5- aminovaleric acid concentration of 16.71 mmol / L was achieved. This study successfully realized the single enzyme( LAAO) synthesis of 5- aminovaleric acid,to lay the foundation for the simple biosynthesis of 5- aminovaleric acid.