White-light diodes (WLEDs) are widely used in high-brightness applications owing to their outstanding advantages. However, current methods for preparing commercial WLEDs significantly deteriorate their optical properties and limit their use in high-power applications. To address this, inorganic materials, such as phosphor-in-glass (PiG), have been recently investigated as practical alternatives. In this study, a series of high-efficiency white-emitting PiG samples were prepared by mixing silicate glass powders with different particle size distributions and different concentrations of Y3Al5O12:Ce3+ (YAG:Ce3+) phosphors. The microstructure, transmittance, and photoluminescence properties of PiG were investigated. When the glass powder with the particle size ranges of 75-150 and 30-48 μm were mixed, at a ratio of 94 : 6, a silicate glass with a thickness of 0.8 mm and a maximum transmittance of 75% in the visible range was obtained. Under excitation with a 450 nm blue-light laser diode, PiG produced white light with a total luminescence efficiency of 194.64 lm W-1 and a total luminous flux of 623.9 lm. These results demonstrate that the optical performance of PiG can be effectively adjusted by adjusting the particle size distribution of silicate glass powder and the mixing concentration of the YAG:Ce3+ phosphor, thereby providing a tuning pathway for smart white-light devices.