The phosphor glass is a promising material to improve the package reliability of high power LED. The phosphor glass is prepared by sintering a mixture of phosphor and borosilicate glass in high temperature. The effects of different preparation conditions on the luminescent properties of the phosphor glass are researched by controlling the temperature, time and the ratio of phosphor. Research results show that the better luminescence performance is obtained when the mixture phosphor and borosilicate glass is sintered at 700 ℃ for 30 min. If the temperature is too low or the time is too short, the phosphor would not be uniformly dispersed in the phosphor glass. If the temperature is too high or the time is too long, the luminescent properties of the phosphor glass would be decreased because of the reactions between the glass matrix and the phosphor. According to the research results, the best luminescence performance is gained as the mix of 3 wt% phosphor.