Series of Li1.sAl0.sGe1.5(PO4)3 glass ceramic samples were prepared through the change of heat treatment temperature from 650 to 1050 ℃.Then the stability of glass ceramic in different types of aqueous solutions has been examined.The structure of glass ceramic samples were characterized by means of high temperature X-ray diffraction and Field Emission Scanning Electron Microscope.And the lithium ionic conductivity were analyzed through AC impedance spectroscopy.