Microstructures are usually fabricated on the surface of optical sheets to improve the optical characteristics. In this study, a new fabrication process with UV (ultraviolet) laser direct writing method is developed to embed microstructures inside the glass. Then the optical properties of glass such as reflection and refraction indexes can be modified. Single- and multi-layer microstructures are designed and embedded inside glasses to modify the optical characteristics. Both luminance and uniformity can be controlled with the embedded microstructures. Thus, the glass with inside pattern can be used as a light guide plate to increase optical performance. First, an optical software, FRED, is applied to design the microstructure configuration. Then, UV laser direct writing with output power: 2.5~ 2.6 W, repetition rate: 30 kHz, wave length: 355nm and pulse duration: 15ns is used to fabricate the microstructures inside the glass. The effect of pattern dimension such as the pitch, the layer gap, and the number of layer on the optical performance is discussed. Machining capacity of UV laser is ranging from micron to submicrometer; hence various dimensions of dot, line width, and layers can be easily embedded in the glass by one simple process. In addition, the embedded microstructures can be fabricated less damage and contamination. Finally, the optical performance of the glasses with various configurations is measured by using Spectra Colorometer (Photo Research PR650) and compared with the simulated results.