NOVELTY - A composite material poly(3,4-dioxoethyl)thiofuran coating carbon nanotube is prepared by ultrasonically dispersing carbon nanotube in deionized water, where solid content is 0.3-3 wt.% of carbon nanotube dispersion; adding oxidant into deionized water, stirring and dissolving to obtain oxidant-containing water (12-16 mol/L); adding monomer 3,4-dioxoethyl thiofuran into 0.12-0.15 times ethyl succinate sodium sulfonate; and performing black solid precipitate washing and drying to obtain carbon nanotube composite material wrapped by poly (3,4-dioxoethyl) thiofuran compound material.    USE - Method for preparation of composite material poly(3,4-dioxoethyl)thiofuran coating carbon nanotube (claimed) used in energy storage device (including super capacitor and lithium ion battery) and sensor.    ADVANTAGE - The method is simple, controllable and large in scale. The composite material does not only has high conductivity but also has high specific surface area.    DETAILED DESCRIPTION - Composite material poly(3,4-dioxoethyl)thiofuran coating carbon nanotube is prepared by:    (A) ultrasonically dispersing carbon nanotube in deionized water, where solid content is 0.3-3 wt.% of carbon nanotube dispersion;    (B) adding oxidant into deionized water, stirring and dissolving to obtain oxidant-containing water (12-16 mol/L);    (C) adding succinate sodium sulfonate into dimethylbenzene, ultrasonic stirring and dissolving to obtain sodium sulfosuccinate (1.3-1.6 mol/L);    (D) adding oxidant-containing water into carbon nanotube dispersion liquid, fully stirring and uniformly mixing;    (E) adding monomer 3,4-dioxoethyl thiofuran into 0.12-0.15 times ethyl succinate sodium sulfonate, stirring at room temperature to obtain carbon nanotube composite material wrapped by poly(3,4-dioxoethyl) thiofuran compound material of black mixed liquid; and    (F) performing black solid precipitate washing and drying to obtain carbon nanotube composite material wrapped by poly (3,4-dioxoethyl) thiofuran compound material.    The vol. ratio of dispersion liquid to oxidant is 1:1. The ratio of dispersion liquid to succinate sodium sulfonate is 1:60.