The present invention belongs to the technical field of photoelectric display devices, relates to an organic electroluminescent device, and particularly relates to an organic electroluminescent device, in which a serial structure is formed by using a specific plan of connection layers that are arranged between adjacent light-emitting units in the device. The device comprises an anode, a cathode, at least two electroluminescent units, which are arranged between the anode and the cathode, and connection layers, which are arranged between adjacent electroluminescent units, wherein each connection layer has a multi-lamination structure, and comprises an n-type doped layer, a p-type doped layer and a spacer layer, which is located between the n-type doped layer and the p-type doped layer, and the spacer layer is made of an electron transport material. Since this type of spacer layer made of an electron transport material can effectively inhibit the diffusion of an n-type dopant in the n-type doped layer to the p-type doped layer on the other side, the problems of driving voltage rise and device aging caused by the diffusion of the n-type dopant are effectively alleviated, thereby significantly improving the service life and stability of a serial organic electroluminescent device.