Bi-based glass powders with nanometer size as the additive of conducting paste were directly prepared by flame spray pyrolysis. The mean size of the powders increased from 37 to 52 nm as the concentration of spray solution was changed from 0.05 to 1 mol/L. The nano-sized glass powders prepared by flame spray pyrolysis had broad peaks at around 28° in the XRD patterns. The glass transition temperature (T_g) of the nano-sized glass powders was 365°C. The glass layer formed from the glass powders obtained from spray solution with low concentration of 0.05 mol/L had clean surface at a firing temperature of 400°C. On the other hand, the glass layers formed from the nano-sized glass powders obtained from spray solutions of 0.5 and 1 mol/L had smooth surfaces at a firing temperature of 450°C. Deviation of composition of nano-sized glass powders obtained from the spray solution with low concentration of 0.05 mol/L occurred in the flame spray pyrolysis process. Therefore, crystallization of the glass powders occurred after firing.