We have studied the effect of chemical functionalization on charge transport property of multiwall carbon nanotube (MWNT) down to the temperature 4.2 K and magnetic field up to 5 T. The resistivity ratio (ρ r = [ρ(T)/ρ(100 K)]) increases with the increment of degree of functionalization at low temperature as the effect of inclusion of disorder in the samples. The variation of resistivity with temperature has been explained by 3D variable range hopping model and Coulomb gap Efros-Shklovskii model, and the result shows that higher degree of functionalization enhances the disorder induced electron-electron interaction. For all the measured temperature and degree of functionalization, MWNTs show negative magnetoresistance. Negative magnetoresistance has been explained by 3D weak localization model.