An organic light emitting diode (OLED) and a manufacturing method thereof are provided. The OLED includes a substrate, and a first electrode serving as an anode, an organic material layer, a second electrode serving as a cathode, and a sealing layer are formed on the substrate in sequence, and the second electrode is a composite transparent structure layer realizing light emission at the top portion. By forming the composite transparent cathode with a light-transmissive top portion, the OLED emits lights from the top portion, so as to effectively enhance a light utilization ratio and a light transmission ratio, and thus not only an aperture ratio of a display screen is enhanced, but also an excellent displaying effect is obtained. Meanwhile, by adding a mesh-shaped current collection layer on a high-resistance semi-transparent metal layer, a current conducting capability is enhanced while ensuring a high light transmission ratio, thereby effectively satisfying the demands for the top-emitting OLED, which is applicable to a double-sided display device. The OLED has a simple structure and simple and reliable manufacturing technique, which thus has a wide application prospect.