The invention relates to a method for preparing nitrile rubber filled with carbon nano tubes and having thermal-oxidative aging resistance. The method comprises the following steps: firstly, preparing a carbon nano tube padding with thermal-oxidative aging resistance, from the point of a molecular structure; mixing the padding with a nitrile rubber matrix, a vulcanizing agent, an acid-absorbing agent and an accelerant; and vulcanizing, thereby acquiring the product. The nitrile rubber prepared according to the method provided by the invention has excellent thermal-oxidative aging resistance, has better mechanical properties and high temperature resistance, can be used as a high-performance sealing material for a long term, and is especially suitable for long-time hot air and oil medium sealing environment.