NOVELTY - Preparing carbon nanotube composite material involves covering carbon nano-tube surface with poly(3-hexylthiophene), where thickness of covering layer is 3-50 nanometer and the added amount of poly(3-hexylthiophene) is 25-80 wt.%. The covered carbon nanotube is placed in reaction vessel and then dimethyl formamide, pyridine and thionyl chloride are added to the reaction vessel in volume ratio of 1-2:1-2:10-20. The obtained material is heated on water bath to 5-100 degrees C and then the heated material is magnetically stirred for 12-60 hours.    USE - Method for preparing poly(3-hexylthiophene) grafted carbon nanotube composite material (claimed).    ADVANTAGE - The method enables to prepare poly(3-hexylthiophene) grafted carbon nanotube composite material in simple and controllable manner, and that improve mobility of carriers for active layer of photovoltaic device material.    DETAILED DESCRIPTION - Preparing carbon nanotube composite material involves covering carbon nano-tube surface with poly(3-hexylthiophene), where thickness of covering layer is 3-50 nanometer and the added amount of poly(3-hexylthiophene) is 25-80 wt.%. The covered carbon nanotube is placed in reaction vessel and then dimethyl formamide, pyridine and thionyl chloride are added to the reaction vessel in volume ratio of 1-2:1-2:10-20. The obtained material is heated on water bath to 5-100 degrees C and then the heated material is magnetically stirred for 12-60 hours. The stirred material is cooled to room temperature and then the cooled material is performed vacuum filtering by using 0.2-0.3 microns micro-pore filter film. The filtered material is washed with tetrahydrofuran and then the washed product is dried in the vacuum drying box for more than 24 hours to obtain acyl chloride carbon nanotube. The acyl chloride carbon nanotube (0.05-0.7 pts.wt.) is placed in reaction vessel and then the obtained material is added with 0.05-0.7 parts by volume of pyridine, 0.05-0. 7 parts by volume of thiofuran monomer and 10-100 parts by volume chloroform and then The obtained material is heated on water bath at 50-100 degrees C and then the heated material is magnetically stirred for 20-60 hours. The stirred material is performed vacuum filtering by using 0.2-0.3 microns micro-pore filter film. The filtered material is washed with chloroform repeatedly. The washed product is dried in the vacuum drying box for more than 24 hours to obtain thiophene monomer grafted carbon nano tube. The thiofuran monomer grafted carbon nano-tube (0.0001-0.0008 pts.wt.) is added in reaction vessel and then acetonitrile (5-30 pts.wt.) is added to the reaction vessel. The obtained material is magnetically stirred for 5-30 minutes to obtain thiophene monomer grafted carbon nanotube dispersion. The thiophene monomer grafted carbon nanotube dispersion is added with 3-hexylthiophene monomer (0.1-0.4 pts.wt.) and then the obtained material is magnetically stirred for 5-30 minutes to obtain thiophene monomer grafted carbon nanotube and 3-hexylthiophene monomer dispersion. The obtained material is added with anhydrous ferric trichloride in reaction vessel and then the obtained material is added with 2-15 parts by volume of acetonitrile. The obtained material is performed ultrasonically dispersing for 5-30 minutes to obtain dispersion ferric trichloride. The anhydrous ferric trichloride solution is added to thiophene monomer grafted carbon nanotube and 3-hexyl thiophene monomer dispersion. The obtained material is added with 10-60 parts by volume of chloroform and then the obtained material is performed reaction 3-12 hours. The reaction material is washed with methanol, toluene, trichloromethane as solvent to colorless and transparent supernatant. The obtained material is performed Soxhlet extraction for 6-8 days to obtain poly(3-hexylthiophene) grafted carbon nanotube composite material. The poly(3-hexylthiophene) grafted carbon nanotube composite material (0.001-0.01 pts.wt.) is placed in reaction vessel and then the obtained material is added with 8-12 parts by volume of tetrahydrofuran.The obtained material is stirred for 5-30 minutes to obtain poly(3-hexylthiophene) thiophene grafted carbon nano-tube composite material dispersion. The sulfur source and cadmium source is added in reaction vessel and then the obtained material is added with 10-50 parts by volume of tetrahydrofuran. The obtained material is performed ultrasonic treatment for 5-30 minutes to obtain sulfur source and cadmium source dispersion and then the sulfur source and cadmium source dispersion is added to poly (3) thiophene grafted carbon nano-tube composite material dispersion. The obtained material is magnetically stirred for 5-30 minutes to obtain sulfur source and cadmium poly(3-hexylthiophene) grafted carbon nanotube composite material of dispersion. The obtained material is added with reducing agent and 5-20 parts by volume of tetrahydrofuran and then the obtained material is performed ultrasonic treatment for 5-30 minutes to obtain dispersion of reducing agent. The reducing agent dispersion is added to sulfur source and cadmium poly(3-hexylthiophene) in grafted carbon nanotube composite material. The obtained material is suspended or dispersed for 3-10 hours and then obtaione product is washed with deionized water to obtain cadmium sulfide-poly(3-hexylthiophene) grafted carbon nanotube composite material.