This study investigated the crystallization behavior in PbO-ZnO-B2O3-TiO2 system sealing glass, inorganic polymer heat-treated by conventional heat and microwave energy. After determining heat-treated temperature for crystallization and characteristic points by DTA analysis, samples were heat-treated in a classical electric furnace and a home-style microwave oven (LG Electronic Co., 2.45 GHz, 700 W). A microwave heat-treated sample had the growth of PbTiO3 crystal at 45$0^{circ}C$, 2$0^{circ}C$ lower than that of a conventionally heat-treated sample. Also, it had crystallinity about 20% higher than the conventionally heat-treated sample. At 49$0^{circ}C$, the size of PbTiO3 crystal in the conventionally heat-treated sample was larger than that in the microwave heat-treated sample due to longer heat-treated time.