In this work, the surface modification and characterized of carbon nanotubes (CNT) from the liquefied petroleum gas (LPG) were investigated. CNT were treated by HNO3 acid to produce the carboxylic groups onto the surface of CNT. These carboxylic groups were used as reaction precursors in the functionalization. CNT and modified CNT were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry and thermal gravimetric analysis (DSC/TGA) X-ray spectroscopy and energy-dispersive X-ray spectroscopy (EDX). The modified CNT has greater versatility for further utilization in different application fields such as biology, nanocomposites, solar energy, etc.