Citric acid was polymerized onto the surface of functionalized multiwall carbon nanotubes (MWCNT-COOH) and MWCNT-graft-poly(citric acid) (MWCNT-g-PCA) hybrid materials were obtained. Due to the grafted poly(citric acid) branches, MWCNT-g-PCA hybrid materials not only were soluble in water but also were able to trap water soluble metal ions. Reduction of trapped metal ions in the polymeric shell of MWCNT-g-PCA hybrid materials by reducing agents such as sodium borohydride led to encapsulated metal nanoparticles on the surface of MWCNT. Herein palladium nanoparticles were encapsulated and transported by MWCNT-g-PCA hybrid materials (MWCNT-g-PCA-EPN) and their application as nanocatalyst toward Heck reaction in different conditions was investigated. The catalytic activity of palladium ions supported by MWCNT-g-PCA hybrid materials (MWCNT-g-PCA-PdCl2) toward Heck reactions is much more than for MWCNT-g-PCA-EPN. Structure, characteristics and catalytic activity of synthesized systems was investigated using spectroscopy and microscopy methods.