Abstract: Investigation was made into the effects of different factors such as concentra-tion of DTPA, pH value of the eluate and flow rate on the separation of Amand Cm from Eu and Pm in the DTPA--α--HIB cation exchange system. Results show that if the following experimental condititions are used, the Amand Cm fraction before the intersection of elution curves of Am and Eu contains100% Cm, 93.8% Am, 4.2% Eu and 1% Pm. Chromatography column:inner diameter 2 mm, height 450mm; Resin: YSG--SO_3Na (20--25μm); Eluate: 1×10~(-3)M DTPA--0.2M α--HIB--pH 3. 00; Flow rate:5 cm/min; Temperature: 50℃.