The invention relates to a tripolar grid-controlled 
cold cathode X-
ray tube, which comprises an 
anode component, a 
cathode component and a vacuum cavity. The 
anode component and the 
cathode componentare arranged in the vacuum cavity. The 
cathode part comprises a cathode and a grid mesh. The 
potential difference between the cathode and the grid mesh can adjust and lead out electrons to bombard ananode target of the 
anode part to generate X-rays. The cathode is made of a super-aligned 
carbon nanotube array. The tripolar grid-controlled 
cold cathode X-
ray tube has the following beneficial effects: the super-aligned carbon nanotubes are used as a 
cathode material, and compared with a common array, the super-aligned 
carbon nanotube array of the material has the advantages that the carbon nanotubes are straighter, are arranged more orderly, have excellent field emission performance and a stable structure, are easy to control as a field emitter, and achieve a better emission effect. The 
getter is added into the vacuum cavity, so that a relatively high vacuum degree can be kept. An electronic focusing function is achieved through the focusing groove and the focusing 
electrode, and a small focus can be achieved.