Silica glasses are often used as the window material of ultra-violet (UV) detector due to having a high UV transmittance. However, this glass is not allowed to connect with other materials directly for its lower thermal expansion coefficient, otherwise, the innerstress can damage the materials. Therefore, using SiO2, P2O5, Al2O3, Li2O as the components, the optical glasses with the high UV transmittance (the maximum up to 56% at 200 nm wavelength), high thermal expansion coefficient and good stability is prepared. The local structure of glasses is studied by magic angle spinning nuclear magnetic resonance (MAS-NMR) and Fourier transform infrared spectroscopy (FTIR). The results show that Si atoms in the glasses are located in the 4-coordinated states and phosphate groups are similar with ultraphosphate groups Q3 originally. And with the Al2O3 content increased, there is a non-bridge oxygen (P-O…Li). At the same time, the average of Al coordination number gradually reduces. The formation of Si-O-P, Si-O-Al and P-O-Al bridge oxygens indicates that the cross-linking among the three components is caused to form a three-dimensional network structure. Moreover, the UV transmittance can be improved when increasing Si-O-Si bonds and decreasing Si-O-P bonds.