The structure of ZnCl2 glass was studied by X-ray diffraction method and the following results were obtained. In the glassy state Zn-Cl distance is 2.32 Å, and the coordination number of Zn is 4. It is elucidated that ZnCl4-tetrahedra link each other at their own corners and construct the layer structure similar to γ-ZnCl2 crystal (shown is Fig. 6). Such model structure is not incosistent with the properties such as melting point, viscosity and etc. Therefore, the structure of ZnCl2 glass is not so much distinctive and is built up to the network consisting of 4-fold coordinated Zn2+ ions. So far as concerning this point, one can find no difference from the well-known structure of conventional glass. Glass-formation range of some binary and ternary systems involving ZnCl2 as a common component were also studied, which were shown in the Table 6 and Fig. 10.