The ivnetnion discloses a novel low temperature-fired glas ceramic composite and the preparing method thereof. And it comprises aluminum nitride and cordierite-based glass in the weight ratio of 35-57 to 65- 43, where the latter comprises SiO2 50-53wt%, Al2O3 20-26wt%,MgO 15-23wt%,B2O3 1.5-5wt%,P2O5 0-2.5wt%,and RxOy 1-6.5wt%, where R in RxOy is one of Bi, Ce and Zn, x=1-2 and y=1-3. When used in advanced electronic package, it has relative density up to above 97.2%, maximum heat conductivity up to 7.5W/m.K, thermal expansion coefficient 3.2- 3.8*10-6K-1, folding strength not lower than 168MPa, fracture toughness not lower than 2.38MPa.m1/2, low dielectric constant, largely improved mechanical properties, etc.