The utility model discloses a lens protective cover attaching device. The device comprises a rack and a horizontal workbench, an adhesive tape supporting and positioning seat is arranged on the horizontal workbench; the rack is further provided with an automatic feeding device used for outputting the lens protection covers. A portal frame is arranged on the horizontal workbench and is positioned right above the adhesive tape supporting and positioning seat; the portal frame is sequentially provided with a first linear driving assembly and a second linear driving assembly which act in the horizontal transverse direction from top to bottom. An adsorption assembly is arranged at the execution end of the first linear driving assembly; the adsorption assembly is used for adsorbing the lens protection cover output from the automatic feeding device and attaching the lens protection cover to the adhesive tape. The horizontal workbench is further provided with a first visual detection assemblyused for detecting the offset of the lens protection cover adsorbed by the adsorption assembly. The execution end of the second linear driving assembly is provided with an industrial camera A used fordetecting the position of a positioning hole A of an adhesive tape located on the adhesive tape supporting and positioning base. The device has the advantages of accurate positioning and fast response.