The invention provides a preparation method of N
omega-methyl-
lysine, which comprises the following steps that: cupric salt is added into
sodium hydroxide solution of L-
lysine,
tosyl chloride solution which is dissolved in
organic solvent is added in under the stirring state, and then
sodium hydroxide solution is added into to have stirring reaction; after the reaction, iodomethane is added in; after the reaction is ended, the pH value is regulated to be 3 to 5 after cooling, and B is prepared
after treatment; the
chemical compound B is heated to have
reflux reaction for 1 to 4h after being mixed with
hydrobromide, and then is cooled, separated and purified, the pH value is regulated to be 3 to 6, and C is prepared
after treatment; and the
acetone solution of the
chemical compound C is mixed with
sodium bicarbonate aqueous solution, 8- hydroxyquinoline is added in, and the N
omega-methyl-
lysine is prepared
after treatment. The preparation method of N
omega-methyl-lysine optimizes the process of a
metal ion complexation method, simplifies the step of protecting Alpha-amino with benzoyl in a traditional synthesis method, simplifies the separation and purification processes and realizes the industrial production of single lysine
methylation, and an intermediate body does not need to be separated and purified.