Chalcogenide glasses (1-y)[0.6Li(2)S-0.4SiS(2)]-y Li4SiO4 which are lithium ionic conductor were synthesized by a liquid nitrogen quenching method. The glass forming region of 0 less than or equal to y less than or equal to 0.075 was determined by both the powder X-ray diffraction and the differential thermal analysis (DTA). From the data of DTA, the glass transition temperature (t(g)) and the crystallization temperature (t(c)) were maximized at y = 0.03 and 0.06, respectively. Also, with the doping of Li4SiO4 into Li4S-Si-2 glass, the stretching vibration peak for the Si-S-Si bridging bond slightly shifted toward higher frequency in the FT-IR spectrum. The electrical conductivity of the glass samples was measured by AC impedance method. The maximum ionic conductivity (sigma(RT) = 1.5 X 10(-3) S cm(-1) at 25 degrees C) was obtained at y = 0.03, and the activation energies (E-a) for ionic conduction increased with increasing amounts of doped Li4SiO4.