The invention provides a surface modification method for a carbon nano tube and belongs to the field of nanotechnology. The method includes step one, uniformly mixing a carbon nano tube which is subjected to acidification by a strong oxidizing acid with a silane coupling agent and deionized water, reacting under a certain condition, filtering, washing, and drying to obtain a primary modified carbon nano tube; step two, uniformly mixing the primary modified carbon nano tube with polyhydric alcohols and a concentrated sulfuric acid, reacting under a certain condition, filtering, washing to neutral, and drying to obtain a secondary modified carbon nano tube; uniformly mixing the secondary modified carbon nano tube with an organic carboxylic acid, an esterification reaction catalyst and N,N-dimethylformamide, reacting under a certain condition by the aid of the protection of inert gases, cooling to the room temperature, filtering, washing, and drying to obtain the surface modification carbon nano tube. When the prepared modified carbon nano tube which is provided with ester groups on the surface is mixed with a polyester resin, the interface-free mixing is achieved, and the heat stability and the mechanical property of the modified polyester resin can be improved.