The present invention, which belongs to the technical field of display technology, provides a microcapsule, a method of preparing the same, and an OLED (organic light emitting diode) display device comprising the same. The OLED display device comprises a microcapsule having a phosphorescent material as a core material, which reduces the probability of the phosphorescence self-quenching and is isolated from water and oxygen, thereby improving the display quality and extending the service life of the OLED display device. Therefore, the OLED display device can solve the problem that the phosphorescence OLED display device in the prior art has a low brightness and short service life.