The present disclosure provides an array substrate which comprises a plurality of sub-pixels distributed in an array arrangement, wherein data lines and power supply signal lines are disposed between two adjacent columns of the sub-pixels; wherein the data lines and the power supply signal lines are prepared respectively on different film layer surfaces, and the data lines and the power supply signal lines at least partially overlap. The present disclosure further provides an OLED display device which comprises the array substrate. The array substrate of the present disclosure has a higher aperture ratio.