We have investigated some methods such as Raman spectroscopy and thermogravimetric analysis (TGA) studies for the nanocomposites multi-walled carbon nanotube-functionalized thiol (MWCNT-SH) by adding to cysteamine with known concentration in nanocomposite. For this study, we synthesized nanocomposite MWCNT-SH by the reaction between multi-walled carbon nanotubes-functionalized carboxyl and the cysteamine. For study of the effect of concentration, cysteamine with different concentrations was used (1, 3 and 5 % weight) and it was called MWCNT-SH1, MWCNT-SH3 and MWCNT-SH5, respectively. Then, the nanocomposite provided was characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The surface structure of nanocomposites can be analyzed and confirmed using Raman and FT-IR spectroscopy. Also, to investigate the thermal stability TGA was used. The study of TGA showed that nanocomposite MWCNT-SH had low thermal stability at temperatures more than 100°C.