The carbon nanotube (CNT) supported palladium catalysts were synthesized by the impregnation method and applied in the hydrogenation of commercial polystyrene (PS) for the first time. The Pd/CNT catalysts displayed a quite excellent hydrogenation activity compared with those of traditional catalysts, e.g., Pd/AC or Pd/BaSO4, and allowed the reaction to be carried out under milder reaction conditions. The physical and chemical properties of Pd/CNTs were characterized by inductively coupled plasma-atomic emission spectrometry, N-2 physisorption, transmission electron microscopy, X-ray diffraction, CO chemisorption, and kinetics analysis. The catalyst characterization results showed that the active metal deposited on the external surface of CNTs with good dispersion. Kinetics analysis showed that the activation energy of Pd/CNTs was similar to comparison catalysts, while the TOF of Pd/CNTs (0.102 s(-1)) was much higher. The high external surface area and the interaction between polymer and CNTs could be the reason for the high performance of Pd/CNTs.