It has been a long-term dream to achieve nanolaser array with uniform laser wavelengths, high densities, and high output powers. However, such kind of nanolaser array is practically quite challenging due to the variations of both bottom-up synthesized nanostructures and top-down etched devices. Herein we explore a simple method to achieve such kind of uniform nanolaser array. By placing a single crystalline CH3NH3PbBr3 nanoribbon onto a gold grating, both of our numerical calculation and experimental results show that the light can be well trapped by a waveguide mode around the air slot area, providing the possibility of high power nanolaser in a narrow air slot. The smallest size of the gap for light confinement is optimized to around 350–400 nm. Consequently, a high-density, uniform nanolaser array has been experimentally realized. And the coupling between different subunits is found to be negligibly small. We believe that this research can boost the progresses of nanolaser array and the corresponding practical applications such as pinpoint detection.