The principle of melt-phase separation process for preparation of nanoparticle TiO2 is based on the adjustment of glass phase-separation structure. TiO2 grain size can be controlled by changing heat treatment temperature. The sample was composed of Na2O-B2O3-SiO2-TiO2 glass system (melted at 1573K). A photocatalytic nanoparticle TiO2 which was loaded on porous glass can be obtained by heat treatment of glass system at various temperatures and then acid washing. The results have shown that the glass phase-separation structure size matches crystallization rate and an optimal photodegradation property of TiO2 is achieved. It was found that the suitable heat treatment condition was at 848K for 12h, although its performance slightly changes with the composition variations.