Our group has been working on developing bio-based graphene-encapsulated no-precious metal catalysts for the synthesis of amines . Previously, using biomass platform compounds citric acid, we prepared the biobased graphene encapsulated Ni and Co heterogeneous catalysts and successfully applied them in the reductive amination of aldehydes in a batch reactor . We also noticed that chitosan, another more abundant biomass platform compound, has been used as catalyst support. However, to our knowledge, a simple and practical preparation of the bio-based chitosan graphene-encapsulated Co catalyst and its utilization in the hydrogenation of nitriles through flow synthesis has not been reported yet. So, herein, for the first time, we used chitosan as the bio-based material to prepare the bio-based graphene-encapsulated Co catalysts and evaluated its reactivity in the hydrogenation of nitriles in an advanced automatic flow reactor. We optimized the process in a micro-packed bed reactor and verified the catalytic effect in a series of aromatic nitrile compounds. After long-term reaction tests, we found that the catalyst was well stable and did not lose reactivity significantly, which provides ideas for the subsequent continuous hydrogenation of nitriles to prepare primary amines in industrial production.