The present disclosure relates to a package structure, a display panel, a display device, and a method for detecting a package structure. The package structure includes a first package layer and a second package layer disposed opposite to each other, and a sealing element between the first package layer and the second package layer for forming a sealed space between the first package layer and the second package layer. The package structure further includes a detecting element located in the sealed space, the detecting element including an oxygen sensitive material, the oxygen sensitive material including a material whose light emission characteristics are changed after exposure to oxygen.