The present invention provides a droxyethylcellulose-carbon nanotube derivative, prepared by original carbon nanotube reacting with an halogenating agent after being ball grinded, purified on the baseof acidizing, carboxylic acid group of the carbon nanotube surface reacting with a binary functional group organic compound to make the lively functional group extend from the surface of the carbon nanotube after being converted to acyl halide group having strong reactive activity, then reacting with trichloro triazine, obtaining a lively carbon nanotube containing trichloro triazine on the surface which can react with hydroxide radical, finally reacting with the droxyethylcellulose via nucleophilic substitution. The mass content ratio of droxyethylcellulose and carbon nanotube is 0.2-1.6:1.The invention also relates to a preparing method of the derivative. The derivative has a friendly environment, has better solubility in organic solvent such as N-pyrrolidoneextraction, dimethylsulfoxide, N, N'-dimethylformamide and N, N'-dimethyl acetamide. The preparing condition of the derivative is easy to meet, and has an ample source of feed, lower cost.