The short- and medium-range orders of GeSe2 chalcogenide glass were studied by using the radial distribution function. The effect of the annealing temperature on the short-range order structure of this glass was investigated. The short-range order structure of as-prepared and annealed GeSe2 chalcogenide glass is regular tetrahedron (edge and corner sharing GeSe4 tetrahedra). The medium-range order of the GeSe2 chalcogenide glass is chemical order associated with topological order. The topological structure of the medium-range order can be described by the Phillips model. The basic structure unit does not change after annealing. Most changes observed in the diffraction patterns may be interpreted in the framework of structural relaxation during which a system tends to attain a metastable equilibrium state. This relaxation can be described by an a process.