Amorphous glasses of the composition xMgO–yP2O5– (100 – x – y)V2O5 with x = 1–5 and y = 5, 10, and 15 mol % are obtained by the melt quenching technique. The amorphous state of samples is confirmed by XRD analysis. The density of glasses is determined by pycnometry. The introduction of 1 mol % magnesium oxide into the glass composition sharply decreases its density, the further increase in the magnesia concentration is accompanied by the graduate increase in density. The conductivity of glasses is measured by two methods: on direct current and by impedance spectroscopy. Comparing these results makes it possible to infer the electronic nature of conduction. The temperature dependence of glass conductivity is linear in the Arrhenius coordinates. For the compositions with y = 10 and 15, the dependence of conductivity on the magnesia content (x) passes through maximum x = 1 mol %. The glass model is build by the self-assembly procedure with the use of the non-constant force field molecular dynamics method. The analysis of configurations reveals that the concentration of 4-cooordinated environment of vanadium passes through a small maximum when 1 mol % MgO is present in the section xMgO–10P2O5–(90 – x)V2O5, which can be considered as an explanation of the conductivity maximum.