This study investigates electron transport properties of a Joule heated multi-wall carbon nanotube at temperatures as high as about 2100 K. Results show that the electrical resistance is temperature-dependent. The temperature dependence of the resistance is inferred to originate from the temperature-dependent intrashell resistance and intershell conductance. The resistance variation was analyzed using a resistive transmission line model. Results well reproduced those obtained using a double shell conduction model where the electrons transport in the outermost shell and the second inner shell.