In this paper, the chemical Functionalization of Carboxylate multi-walled carbon nanotubes by methyl (triphenyl phosphoranylidene) acetate have been investigated. Phosphorus Ylides are important compound in organic chemistry. At first, methyl (triphenyl phosphoranylidene) acetate, synthesized from salt metod in two steps: the formation of the phosphonium salt and the deprotonation of the latter to form the ylide. MWNT-Slide is obtained through MWNT-cocl with methyl (triphenyl phosphoranylidene) acetate, which is confirmed by FT-IR, SEM and elemental analysis. The functionalized MWNTs were dispersed very well in solvent of dimethylformamide (DMF), and the high stability of dispersed suspension could be maintained for more than 1 week without MWNT precipitation. These Functionalization have been chosen due to P=C and C=O active sites in MWNT-ylide for future application.