The invention discloses a bidentate aza-carbene manganese catalyst and a preparation method and alkylation synthesis application thereof. The catalyst disclosed by the invention has a wide accommodation range to a substrate and can be used for catalyzing the synthesis of C-C and C-N bond compounds of different structures under a moderate condition, alcohol is directly taken as a raw material for reaction, and a reactant can be easily obtained and is reproducible. Compared with a traditional aldehyde reactant, the catalyst disclosed by the invention is more stable, easy to operate, low in toxinand environmentally-friendly.