Embodiments of the present disclosure provide a display panel, a manufacturing method thereof, and a display device. The display panel includes a substrate, and a plurality of pixel units on the substrate. The pixel units are arranged in an array, and two adjacent columns of pixel units are spaced apart from each other to form an interval area. Each pixel unit includes a pixel defining layer and sub-pixels, and the sub-pixels are in pixel areas defined by the pixel defining layer. Cathodes of all sub-pixels in one column of pixel units are connected as one single piece.