Aiming to find an excellent anode material for Li-ion batteries, we report the two-dimensional Zr2B2 monolayer combining the density functional theory and crystal structure prediction techniques. We find that the monolayer Zr2B2 has initial metallicity and good stability, and keeps excellent electrical conductivity during the whole process of lithiation. The adsorption energy of lithium is -0.628 eV, which is enough to make sure the stability of the processing of lithiation. Furthermore, the ultralow diffusion energy barrier of Li ion on the surface of the monolayer Zr2B2 (17 meV) indicates an excellent charge-discharge rate. The theoretical specific capacity of 526 mA h g(-1) is larger than that of the commercial graphite electrode. All these results propose the hexagonal monolayer Zr2B2 as an excellent anode material for Li-ion batteries.