The invention belongs to the technical field of carbon nanotube, and discloses a flame method modified carbon nanotube, and a preparation method and applications thereof. According to the preparationmethod, ethanol flame combustion is adopted for surface modification of carbon nanotube so as to obtain TCNTs with a relatively large pore diameter as a matrix; in the presence of a nickel salt catalyst, flame combustion time and temperature are controlled, and in-suit growth of nanometer scale short carbon nanotubes (FCNTs) on the internal wall and the external wall of the TCNTs with certain spatial constraint effect is realized, and carbon nanotube composite fractal structures with different modification effects are obtained; when the flame method modified carbon nanotube is taken as a lithium ion battery anode material, excellent lithium ion storage ratio capacity is achieved. Compared with chemical vapor deposition method in the prior art wherein expensive production equipment, enclosed production environment, and relatively temperature (higher than 650 DEG C) are needed, the preparation method possesses following advantages: only alcohol flame is needed, open production environment is enough for production, and treatment temperature is relatively low (as low as 450 DEG C); obvious competitiveness is achieved; and large scale product is more convenient to realize.