The invention discloses a UV lamp sterilizing device characterized by being composed of a mounting base plate, an electronic ballast, a lamp holder, a UV lamp tube, and a metal mesh lampshade coated with a photocatalyst-titanium dioxide coating layer on the inner surface; the electronic ballast, the lamp holder and the metal lampshade are fixed on the base plate; the UV lamp tube is connected on the lamp holder, has the length direction parallel to the base plate, and is completely shaped by the metal lampshade; the output end of the electronic ballast is connected with the wiring end of the lamp holder through a wire. The UV lamp sterilizing device has the advantages of simple structure, small size, and convenient installation and maintenance, and can be applied to various types of air conditioners.