Abstract: In the determination of the fission yields of lanthanide nuclides, lanthanide elements, with carriers of 1-2 mg per element are separated from one another by means of high performance chromatography on a polystyrene-sulfuric acid cation exchange resin column consisting of stainless steel tube (4.1×500 mm) with concentration gradient elution using α-hydroxyisobutyric acid of 0.07M and 0.50 M at pH 5.8. The cocentration gradient is effected by a simple gradient device which consists of two circular cone vessels (Fig. 2). The effects of the flow-rate, the temperature and loading on the chromatographic parameters are studied in detail. The results show that (1) a plot of the effective plate height (H) with the.flow-rate is a straight line, the slope of which increases with the atomic numbers of lanthanide elements; (2) the lanthanide elements in the cation exchange-α HIBA system could be divided into three groups according to the dependence of their distribution coefficients (Dv) on the temperature; and (3) the spectrum bands spread and the resolutions and the effective plate numbers decrease when loading of column increases. The effective plate numbers of lanthanide elements for a given loading decrease as the atomic numbers increase.Under the condition selected, the time for the separation of all the lanthanide elements is about 90 min with a recovery of 95% and more for each lanthanide element excepting Lu and Yb.