Provided are an OLED (Organic Light-Emitting Diode) display panel and a manufacturing method thereof. The OLED display panel comprises a plurality of scan lines (Sn), data lines (D1 and D2), and power lines (VDD), wherein the scan lines (Sn) and the data lines (D1 and D2) define a plurality of pixel groups arranged in a matrix; wherein each pixel group has two sub-pixels, two sub-pixels in a same pixel group connected to a same power line (VDD) and arranged in mirror symmetry with respect to the power line (VDD), and wherein the data lines (D1 and D2) connected to the two sub-pixels in the same pixel group are located on different structural layers. On one hand, the probability of occurrence of a short circuit between the data lines (D1 and D2) is effectively reduced, and crosstalk between the data lines (D1 and D2) is significantly eliminated. On the other hand, the pixel area can be reduced based on existing apparatuses and process conditions, improving the PPI of the OLED display panel, and enhancing the resolution of the OLED display panel.