The electronic transport properties of hybrid graphene nanoribbons constructed by substituting C atom chain into B (N) atom chain are investigated through using the density functional theory in combination with the nonequilibrium Green's function method. It is found that the hybrid nanoribbon with armchair edge transits from semiconducting to metallic. While the transport properties of hybrid B (N) system with zigzag edge are highly improved with the transmission conductance around the Fermi level increasing to 6G0 (5G0). All these unique transport properties are mainly attributed to the coupling effect between B (N) atoms and C atoms at the interface of hybrid systems, which introduces a pair of bonding and antibonding bands around the Fermi level. The results indicate that such hybrid system is an effective way to modulate the transport properties of graphene nanoribbons.