Novel polycrystalline TiN coated ZnO core-shell heterostructure nanorods have been prepared on carbon paper substrate via a low-temperature hydrothermal and sputtering process. The core-shell emitters exhibit a highly efficient field-emission performance with a low threshold of electric field similar to 0.72 V/mu m, and a high emission current density similar to 16.41 mA/cm(2), a level that is the highest of ZnO emitters reported to date. The improved field-emission characteristics may be attributed to the unique materials combination of ZnO core and TiN shell, resulting in the conductivity enhancement, emission sites increase, and the work function reduction. Our results demonstrate that ZnO/TiN core-shell emitter will be a distinguished candidate for electronic source devices.