The invention provides a methylation method for amine. The methylation method is characterized by comprising the following steps: taking carbonate as a catalyst, taking carbon dioxide as a C1 source, taking diphenylsilane as a reducing agent, and reacting primary amine or secondary amine in an acetonitrile solvent, thereby obtaining a corresponding methylation product. The invention develops a new methylation method for amine, wherein the used raw materials are low in cost and low in toxicity, the reaction operation is simple, and the yield is high.