The invention provides a purifying method of a macroscopic body of a carbon nano tube. The method comprises the following steps: S1, constructing an electrolytic device, wherein the electrolytic device comprises a cathode, an anode and an electrolyte which are located in an electrolytic bath; and S2, attaching the macroscopic body of the carbon nano tube to the anode and electrifying for electrolysis and purification. Compared with the prior art, the macroscopic body of the carbon nano tube is purified by the electrolytic method, so that the problem that metal catalysts inside the macroscopic body of the carbon nano tube are hard to remove for the macroscopic body of the carbon nano tube soaked by a conventional acidic solution, and the macroscopic body of the carbon nano tube is thoroughly purified. The purifying method provided by the invention is simple and convenient in process and method, low in cost, wide in application and suitable for popularization and application on a large scale.