Fused silica glass is a kind of indispensable material in high-energy laser system, and the damage of it has been one of the bottlenecks restricting the energy of system. In this paper, laser pulse shock wave was used to break down the fused glass samples, then the cause of the morphology of fractures on fused silica glass surface as well as internal phase transition were investigated experimentally and theoretically by multi-spectrum detecting of the samples before and after fracture, and the relationship between fracture morphologies and phase transition structure was explained from macro to micro. The fracture of the fused silica was induced by laser plasma shock wave, and during the shock wave, the tip of hoop stress produced from the inside glass would promote the crack propagation outward. We found that the whole fracture region could be divided into hackle zone, mist zone and mirror zone by morphology differences produced by the tip of hoop stress. The transmittance spectra and energy dispersive spectrometer were used to detect the samples before and after fracture. The results showed that the decrease of the transmittance and band gap of the glass were induced by the cracks, and the oxygen free or absent appeared in the fracture zone. Using the Raman spectrum to detect the different morphological areas of samples before and after broken, we found that the Si—O—Si band of fused glass breakage and recombination could reduce the relative content of three- and four-number rings structures corresponding to the stishovite and coesite of hackle zone, mist zone and mirror zone at the macro level. This kind of changes destroyed the mesh topology severely and induced the material fracture zone transforming to a higher density phase. From the micro level, the non-bridging oxygen hole center and E’center led to the decrease of the optical band gaps as well as transmittance which seriously affected the performance of glass.