A graphene-wrapped Co-based catalyst was successfully prepared by in-situ synthesis. The catalyst used chitosan, a biomass nitrogen source, as a carrier material and was successfully applied in a continuous micropacked bed reactor to hydrogenate BN to benzylamine. The effects of temperature, pressure, ammonia concentration, and the residence time of the material flowing through the reaction tube on the hydrogenation reaction were evaluated. At 80 °C, 0.5 MPa H2, and a flow rate of 0.5 mL/min, the BN conversion rate and BA selectivity were higher than 99%. The microreactor has excellent heat and mass transfer performance, and various aromatic nitriles were well tolerated under optimized conditions, and good yields were obtained under mild conditions. Surprisingly, after longterm catalyst stability testing, the Co@CS catalyst had no significant deactivation and showed excellent stability. This flow hydrogenation method uses nitrile as a simple and safe raw material to prepare primary amines, which is expected to become an efficient and practical synthetic route for various amine-containing functional materials. The continuous flow process also provides the possibility for industrial scale-up.