The invention relates to a synthetic method of N, N-dimethyl cyclohexyl-1, 2 amine, mainly solving the technical problem of difficulty in later-period purification of the N, N-dimethyl cyclohexyl-1, 2 amine. The synthetic method includes exposing free amino in an open loop mode under the condition of ethyl alcohol backflow after reaction between cyclohexyl-1, 2-diamine and methyl acetylimino, taking water and formic acid as solvents, adding formaldehyde for overnight backflow to generate a dimethylamino compound, removing acetyl by HCl and performing rotary drying to obtain a final product. The product of the synthetic method is mainly applied to catalyst ligands.