For the first time, a new kind of nanorod-shaped polycarboxylic acid slump-retaining agent was synthesized.TEM experiment showed that the nanorods were bound together as macromolecular aggregates in solution.Application performance studying suggested that this kind nano-sized polymer material had excellently plasticity-retaining performance in cement-based materials and could improve endurance performance of hardened cement-based materials distinctly.The concrete with an initial slump of 2-9 cm can achieve three hours plasticity-retaining performance with the help of this kind nanorod.The product has extremely wide application value in the market.