Disclosed are carbon nitride (C.sub.1-xN.sub.x) nanotubes with nano-sized pores on their stems, their preparation method and control method of size and quantity of pores thereof.The present invention further has an object of providing the C.sub.1-xN.sub.x nanotube with pores having the size of not more than 1 nm over structure of the nanotube and a method for preparing the same.Another object of the present invention is to provide the control method of the size and quantity of pores with size of not more than 1 nm in the preparation of the C.sub.1-xN.sub.x nanotube with the pores over structure of the nanotube.The present invention can produce the C.sub.1-xN.sub.x nanotube with nano-sized pores by reacting hydrocarbon gas and nitrogen gas through plasma CVD in the presence of metal catalyst particles, wherein x ranges from 0.001 to 0.2.