An OLED is disclosed which includes an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode. The light emitting layer includes a first phosphorescent light emitting layer, a blue fluorescent light emitting layer, and a second phosphorescent light emitting layer, which are stacked along a direction from the anode to the cathode. The first phosphorescent light emitting layer includes a material capable of conducting holes and blocking electrons. The second phosphorescent light emitting layer includes a material capable of conducting electrons and blocking holes. The blue fluorescent light emitting layer includes a material capable of conducting both holes and electrons. With the phosphorescent light emitting layers having a function of restricting charges, the exciton recombination zone is constrained in the blue fluorescent light emitting layer.