An OLED package structure includes a first outer bound confinement layer formed on an OLED device, a first outer bound confinement layer arranged on the first inorganic layer and enclosing and delimiting a confinement space, a first organic layer formed on the first inorganic layer in the confinement space, and a second inorganic layer arranged on the first organic layer and the first outer bound confinement layer, such that a peripheral portion of the second inorganic layer is positioned on and supported by the first outer bound confinement layer and a central portion of the second inorganic layer is partly received in the confinement space to have a bottom of the second inorganic layer positioned on and contacting a top of the first organic layer.