From the X-ray diffraction data of Se1-xGex chalcogenide glasses (0<x<0.3) the radial distribution function (RDF) has been calculated. Using the RDF results the short- and medium-range order has been discussed. The results of the RDF indicate that the basic structure unit of the system is tetrahedral and the atoms are distributed according to the chain-crossing model and the edge- as well as corner-sharing tetrahedra. The amorphous and the crystalline phases have the same structure unit (for 0.2 at Ge). The germanium content does not have any influence on the basic structure unit. For x>0.1, the results indicate that the amorphous phase has medium-range order or topology order