The present disclosure relates to a packaging structure of an OLED device, a display device, and a packaging method of an OLED device. The packaging structure of an OLED device comprises: a substrate, an OLED device on the substrate, a first layer on the OLED device, wherein, the packaging structure of the OLED device further comprises a first blocking layer positioned outside the first layer for defining the first layer, and wherein the first blocking layer has a margin portion in its corner position.