On the base of this principle, we developed a novel TiO2-immobilized photocatalytic reactor, named horizontal circulating bed photocatalytic reactor (HCBPR), in which photocatalyst TiO2 is immobilized on polyurethane foam (PF) cubes and the PF cubes are suspended and circulated in the reactor, so as to get high mass transfer rate of pollutant to TiO2 surface.