In order to obtain high yield and purity, the synthesis method of agomelatine is studied. Agomelatine is synthesized with methyl-phenoxide and succinic anhydride by Friedel-crafts acylation, catalytic hydrogenation reduction, cyclization, Knoevenagel condensation, aromatization, NaBH₄/NiCl₂·6H₂O reduction and acylation, and the reaction conditions and parameters are optimized and improved. The results show that the optimum conditions are as following: Catalytic hydrogenation reduction is applied instead of conventional Huang Minglong reduction or Clemenson reduction, with the amount of Pd/C is 20% in solvent anhydrous ethanol, under the pressure of 1 MPa, temperature of 35 ℃, and the yield is up to 86.8%. Knoevenagel condensation is optimized, with benzyl amine and formic acid as catalyst, n(7-methoxy-1-naphthalene ketone)∶n(cyanoacetic acid)∶n(benzyl amine)∶n(formic acid)=1∶1.8∶0.3∶0.3, and the transformation rate is 95.6%. In NaBH₄/NiCl₂·6H₂O reduction step, Boc anhydride is specially added to protect the amino group and reduce by-product, and the yield of 72.5% is obtained. Under the optimized conditions, the total yield is 26%, and the purity is 99.79%. The structures of target compounds are confirmed by ¹H-NMR and ¹³C-NMR. The process route of catalytic hydrogenation reduction method is green and environmentally friendly, the reaction conditions are mild, and the post-treatment is simple, which provides a theoretical reference for improving the reaction yield and purity of the product of agomelatine.