The present disclosure belongs to the technical field of catalyst preparation, and provides a polynorbornene/carbon black-cross-linked three-dimensional network-immobilized bimetallic copper/gold (PNBI/CB-Cu/Au) nanocatalyst, and a preparation method and use thereof. Metallic copper and gold both exist in a form of nanoparticles in the catalyst and are uniformly dispersed, and further enhancing a catalytic performance. Moreover, the carrier is a polynorbornene/carbon black-cross-linked three-dimensional network, and a relative content of free hydroxyl groups in the catalyst is controlled by changing a monomer ratio to adjust a hydrophilic-lipophilic balance value of the catalyst, adapting to a reaction of an organic phase with an aqueous phase. Furthermore, the catalyst is insoluble in conventional solvents, and has a desirable effect in immobilizing nanoscale metallic copper, prolonging a service life of the catalyst.