The photocatalyst filter screen is a lattice doping of nano-sized powders and various nano-sized light-sensitive semiconductor media to ensure sufficient ventilation and contact. As long as there is light (ultraviolet rays), its catalytic ability can be restored. The activated media is not lost, can regenerate for further use, and can be used for a long period of time. Therefore, it has become a new type of air purification filter screen used by manufacturers of air conditioners, air purifiers, and automobile purification systems.