The Li10GeP2S12-type solid electrolyte was obtained by a liquid-phase process. A small amount of solids (1-3wt%) in MeOH solvent formed a homogeneous solution. Stirring for 2 h and subsequent drying provided an amorphous Li-Ge-P-S. Sintering of the powder at 550 degrees C for 8 h crystallized the Li10GeP2S12 providing a superionic conductivity of over 10(-3)Scm(-1). The further study of this liquid-phase synthesis could enable the development of a battery fabrication process using the liquid-phase.