NOVELTY - A carbon nano pipe grafted glass fiber multi-scale reinforcement reinforced polyimide composite material is prepared by (A) preparing purified carbon nano pipe, (B) preparing acidified carbon nanotube, (C) preparing carbon nanotube whose surface is grafted with glass fiber multi-scale reinforcement, (D) preparing carbon nanotube whose surface is grafted with functional glass fiber multi-scale reinforcement, and (E) preparing the composite material. The step (E) comprises mixing carbon nanotube and polyimide to obtain desired carbon nanotube through vacuum drying.    USE - Method for preparing carbon nano pipe grafted glass fiber multi-scale reinforcement reinforced polyimide composite material (claimed) used for aerospace, transport and communication trade, wind power generation and mechanical and electronic field.    ADVANTAGE - The method is simple, improves adhesive performance of glass fiber and resin matrix, thus improving interface bonding strength of the composite material.    DETAILED DESCRIPTION - Carbon nano pipe grafted glass fiber multi-scale reinforcement reinforced polyimide composite material is prepared by (A) preparing purified carbon nano pipe, (B) preparing acidified carbon nanotube, (C) preparing carbon nanotube whose surface is grafted with glass fiber multi-scale reinforcement, (D) preparing carbon nanotube whose surface is grafted with functional glass fiber multi-scale reinforcement, and (E) preparing the composite material. The step (A) weighing dry carbon nanotube (0. 1-1x 10 g) and inorganic acid (10- 1x 104 mL), and stirring for 0.1-24 hours at 1-20 kHz ultrasonic or centrifuging at 10-106 revolutions/minute (rpm); heating to 20-150 degrees C, reacting for 0.1- 48 hours, diluting and washing microporous filtering film, and filtering deionized water; and repeatedly washing until filtrate is neutral, vacuum drying at 25-150 degrees C for 1-48 hours to obtain purified carbon nano pipe. The step (B) comprises mixing purified carbon nanotube (0.1- 1x 10 g) and strong oxidizing acid (1-1x 103 mL), processing for 0.1-80 hours under 1-20 kHz ultrasonic wave, and heating to 25-120 degrees C; stirring and refluxing for 0.1-80 hours, diluting and washing through deionized water, and filtering super microporous filtering film; and repeatedly washing until filtrate is neutral for 1-48 hours and vacuum drying at 25-200 degrees C to obtain acidified carbon nanotube. The step (C) comprises mixing acidified carbon nanotube (0. 1-1x 10 g) and organic solvent (1-1x 10 3 mL), ultrasonic stirring at 1-20 kHz for 1-24 hours, and uniformly dispersing acidified carbon nanotube in organic solvent; adding glass fiber and reacting at 5-120 degrees C for 1-96 hours, filtering and washing, and vacuum drying for 0.1-48 hours at 25-200 degrees C to obtain carbon nanotube whose surface is grafted with glass fiber multi-scale reinforcement. The step (D) comprises putting obtained carbon nanotube in step (C) (0.1-1asterisk103 g) into coupling agent solution (1-1asterisk103 mL), reacting at 5-120 degrees C for 1-96 hours, filtering, and drying at 25-200 degrees C for 0.1-48 hours to obtain carbon nanotube whose surface is grafted with functional glass fiber multi-scale reinforcement. The step (E) comprises mixing carbon nanotube obtained in step (D) (0. 1-1x 103 g) and polyimide (1- 1x 103 g) to obtain desired carbon nanotube through vacuum drying.