Structural analysis of molten Bi4Ge3O12(2Bi2O33GeO2), Bi2GeO5(Bi2O3GeO2) and Bil2GeO20(6Bi2O3GeO2) has been carried out using the high-temperature energy dispersive X-ray diffraction (EDXD) method. The local ordering unit structure of GeO4 tetrahedra is recognized in the bismuth germanate (BGO) melts of the three compositions. On the other hand, distorted octahedral unit structure of BiO6 is suggested in the Bi2GeO5 melt. Specific heats of these three BGO compounds have also been estimated from the differential scanning calorimetry (DSC) measurements, but no particular temperature dependence is detected after melting.