The present invention provides a silica-based materials with direct band gap and light emitting capable of achieving a CMOS process and a preparation method thereof. The method comprises the steps of:preparing silica-based materials, wherein the silica-based materials are germanium materials or silicon germanium alloy; filling inert gas atoms and/or atoms with small atom ordinal numbers into partof interstitial void positions of the silica-based materials to achieve lattice volume expansion to achieve conversion of an energy band structure from indirect band gap to direct band gap and obtainsilica-based materials with direct band gap and light emitting. Besides, the present invention further provides a luminescent silica-based device. The preparation method provided by the invention iscompatible with the CMOS integration circuit process to achieve direct band gap and light emitting of germanium and silicon germanium alloy materials, the luminous efficiency of the silica-based materials is similar to that of III-V group direct band gap materials such as InP and GaAs so as to provide a new solution scheme for an on-chip light source required by achieving silica-based or germanium-based electronic integration technology.