A cathode of a lithium-air battery includes a carbon nanotube composite film and a protecting layer. The carbon nanotube composite film includes a carbon nanotube network structure and a catalyst in particle form located in the carbon nanotube network structure. The carbon nanotube composite film is disposed on a surface of the protecting layer. The protecting layer allows conduction of lithium ions while preventing organic substances in an electrolyte of the lithium-air battery reaching the carbon nanotube composite film. A lithium-air battery is also disclosed.