An encapsulation structure for OLED device comprises a glass substrate, a glass cover plate, an OLED device and a sealing layer. The glass substrate has a recessed portion, the glass cover plate is located at an opening of the recessed portion, and a periphery of the glass cover plate and the glass substrate are bonded through a frit barricade formed by melted glass powders, so that the glass cover plate and the glass substrate have an integral structure, a closed cavity is formed by the glass cover plate and the recessed portion, and both the OLED device and the sealing layer are located within the closed cavity. With the above encapsulation structure, water vapor and oxygen gas can be prevented from entering the OLED device, and service life of the OLED device is prolonged. There is further disclosed an encapsulating method.