Abstract: The separation of carrier-free cesium from fission products has been investigated using ion-exchange chromatography with zirconium phosphate inorganic exchanger and anion exchanger resin. The influence of temperature on the recovery of cesium and the eluting conditions of the main fission products using zirconium phosphate exchanger are examined in details. The decontamination of uranium and other fission products for the cesium sample through anion exchanger resin column are also measured. This results show that the chemical recovery of cesium from fission products is more than 90% and the decontamination factors of Zr, Nb, Ce, Ru are higher than 6.2×10~2. When anion exchanger resin is employed, a decontamination factor of uranium can reach over 10~4 for the separation of cesium. The separated cesium sample is radiochemical pure, and can be used as a sample in the measurement of the thermal neutron cross section of ~(135)Cs.