The invention discloses an iron tower corrosion preventing device based on solar power generation, and belongs to the technical field of iron towers. The corrosion preventing device comprises a solar power generation module and an electrochemistry corrosion preventing module. The solar power generation module comprises a solar panel, a photovoltaic controller, a storage battery and a potentiostat, all of which are sequentially connected through a wire. The output cathode end and the zero position cathode connecting end of the potentiostat are both connected with the lower middle portion of an iron tower. The electrochemistry corrosion preventing module comprises an anode block, an anode bed and a reference electrode. The anode block and the anode bed are both connected with the output anode end of the potentiostat. The reference electrode is connected with the sampling signal input end of the potentiostat. According to the iron tower corrosion preventing device, the impressed current cathode protection technology is utilized, the problem that in the coastal area or the industrial area with the severe environment, the corrosion rate of the iron tower is increased is solved, the defects of the traditional galvanizing technology are overcome, the service life of the iron tower is effectively prolonged, steel resources are saved, and the investment cost is reduced.