Cutting two-dimensional (2D) CN2 sheet along specific crystallographic orientations to construct CN2 nanoribbon, its electronic structure is investigated systemically. We show by first-principles calculations that the electronic properties of CN2 nanoribbon exhibit response to applied electric field and strain. The lowest conduction band and highest valence bands of the spin-up and spin-down states approach to the Fermi level respectively with increasing the strength of the electric field and tensile strain. More interestingly, an applied electric field can transform the nature of the CN2 nano...