The invention relates to a method for preparing a columnar nanometer heating electrode, which comprises the following steps: firstly, depositing a layer of TiN film of which the thickness is between 100 and 300 nanometers on a substrate, and using submicron CMOS standard process exposing technique to form a photoresist pattern of which the diameter is between 200 and 300 nanometers on the TiN film; secondly, using the shape of an O2 gas trimming photoresist in a reactive ion etching technique to reduce the size of the photoresist pattern to be around 40 to 100 nanometers, and etching the TiN film by using a plasma etching technique; and finally, washing the photoresist to obtain the columnar nanometer heating electrode of which the size is between 40 and 100 nanometers. The method not onlyavoids the difficulty of using an exposing technique under 100 nanometers directly and reduces the manufacturing cost, but more importantly reduces the operating current and the power consumption ofa phase change memory. The method not only is applicable to preparing a small-size nanometer heating electrode for the phase change memory, but also is applicable to preparing nano-electrodes requiredby other electronic devices particularly nano-electronic devices, and has great application value.