Abstract: The hydroxylated multi-walled carbon tubes (MWCNTs) was synthesized by surface-modification of MWCNTs. The MWCNTs grafted poly (caprolactone) (PCL) based macroinitiator was obtained by the ring opening polymerization of caprolactone which was catalyzed by MWCNTs-OH and further treated with 2-bromoisobutyryl bromide. The MWCNTs/PCL-b-PNIPAM composite was prepared by in situ atom transfer radical polymerization (ATRP). The products were characterized by FTIR, TGA, XRD, NMR and TEM. The crystallization property and miscibility of MWCNTs/PCL-b-PNIPAM composites in chloroform solvent were observed. The XRD results show that the crystallization peak of MWCNTs/PCL-b-PNIPAM composites is similar to the PCL-b-PNIPAM block copolymer, and MWCNTs/PCL-b-PNIPAM composites have a good miscibility in chloroform solution.