The invention relates to a novel process and method for preparing a porous glass marble having photocatalysis activity capable of floating on the water surface. The invention is characterized in by: (1) simply preparing the porous glass marble having a certain intensity capable of floating on the water surface by using silica gel, glass powder and sodium bicarbonate as raw materials; (2) successfully fixing anatase TiO2 on the surface of porous glass marble by adopting an impregnation method. In one hour, a methylene blue solution with the concentration of 2*10<-5> mol L<-1> can be fully degraded, which shows that the porous glass marble with TiO2 supported thereon has good photocatalysis activity.