The structure analysis of sodium tetragermanate glass has been carried out on the basis of X-ray diffraction using the pair function method. The thermodynamically stable Na 4Ge 9O 20 and metastable wadeite type Na 2Ge 4O 9 crystals, precipitated in the Na 2O·4GeO 2 glass on reheating, were selected as starting structure models of the glass. As to the structure of glass in the range up to 3.5 Å, that of the wadeite type Na 2Ge 4O 9 crystal in which a GeO 6 octahedron is connected with GeO 4 tetrahedra, composing Ge 3O 9 rings by sharing corner-oxygens, and the content of 6-fold coordinated Ge 4+ ions, N 6, is 25%, was preferred to that of the Na 4Ge 9O 20 crystal in which GeO 6 octahedra form a group of Ge 4O 16 by sharing edges and N 6 is 44.4%. In order to explain the longer range structure of the glass, the Ge 3O 9 rings in the Na 2Ge 4O 9 model were reconstructed to form (GeO 3) n chains of GeO 4 tetrahedra. Thus, it has been proposed that in the Na 2O·4GeO 2 glass a GeO 6 octahedron is linked to six GeO 4 tetrahedra forming (GeO 3) n chains by sharing corner-oxygens and the ratio of GeO 6 to GeO 4 is 1 to 3. This structure model does not contradict Zachariasen's rule on glass formation and crystallization behavior of the glass.