The carbon nano-tubes were extracted from the carbon nano-powders what was the byproduct in coal-coking industry by oxidation method. X-ray diffraction and transmission electron microscope were used to determine the size and morphology of the carbon nano-tubes. And the surface structure was studied by IR spectrum. The results showed that the structure of carbon nano-tubes was same as the structure of graphite whose d₀₀₂ value was 0.3496 nm. The carbon nano-tubes had exhibited good electrochemical capability whose discharge capacity was 584.3 mA·h/g at the first cycle. The negative materials making up of carbon nano-tubes (20wt%) and graphite powder (80wt%) showed good cycle capability whose discharge capacity was 490.1 mA·h/g at the first cycle.