The present disclosure discloses an OLED display panel and a manufacturing method thereof, including: forming a first anode layer on a substrate; forming a conductive layer, a first pixel defining layer and a protective layer covering the conductive layer on the first anode layer; forming a first OLED pixel layer on the first anode layer; forming a first cathode layer on the OLED pixel layer; forming a second anode layer on the first cathode layer; forming a second OLED pixel layer on the second anode layer; and forming a second cathode layer on the second OLED pixel layer. In the above way, the times of the precision mask used in the manufacturing process is greatly reduced, and the space occupied by the stack structure in parallel with the three primary colors is greatly reduced, thereby greatly improving the pixel resolution.