The invention provides a reflective X-ray source structure of a patterned carbon nanotube cathode. The reflective X-ray source structure comprises a carbon nanotube, a conductive base, an insulation cover, an insulation gasket, a focus barrel, a grid mesh, an anode target, a berylium window and a sphere tube. The bottom of the insulation cover matches the conductive base. The carbon nanotube, the insulation gasket and the grid mesh are mounted on the top of the conductive base in sequence from bottom to top. The focus barrel is arranged on the top of the insulation cover. After voltages are applied on the conductive base and the grid mesh until a threshold value arrives, the intensity of a current generated by the carbon nanotube is controlled through the grid mesh; electrons are pulled out from the end face of the carbon nanotube; the electrons are focused through the focus barrel, light spots are formed and hit the anode target; and X rays are generated and are transmitted towards the berylium window. Through adoption of the reflective X-ray source structure, the problem that the working temperature is high, the power consumption is high, the starting speed is slow, the service life is short and a ray source is not easy to realize due to the fact that a thermionic cathode is taken as an electron source of a traditional X-ray source can be solved, and moreover, field emission is controlled.