The (BaO, R2O)-Nb2O5-SiO2 glasses (where R = Li, Na and K) were prepared by melt-casting method, and the structures were investigated by Raman spectrum, which confirmed that NbO6 units existed in the glass network. The influence of different network modifiers was investigated on the thermal stability, dielectric properties and breakdown strength. All glasses showed improved dielectric constant value of 17-23 with good temperature stability and considerable breakdown strength of 3-4.5 MV/cm with the thickness of 30-50 mu m. Particularly, the glass composition of BaO-Na2O-K2O-Nb2O5-SiO2 with highest breakdown strength showed a high energy storage density of similar to 19 J/cm(3) and a short discharge period of similar to 9 ns, indicating a promising candidate in pulsed power application. (C) 2017 Elsevier B.V. All rights reserved.