Abstract: The possibility of neutron capture production of ¹⁷¹Tm using natural erbium oxide as target material was investigated by irradiation in the middle hole of Xi’an pulsed reactor. The influence of isotope composition of erbium and amount of target material was investigated. Ion-exchange chromatography method using Dowex50×8-400 and 2-hydroxyisobutyric acid (2-HIBA) was performed to separate Tm from the activated material. The influence of sample load, fluent pH, length of the resin bed and temperature on the separation was discussed. Experiment results show that, (1) the composition and the amount of the target material have little influence on the activated productivity of ¹⁷¹Tm; (2) the sample load, the pH of fluent, the length of the resin bed and the temperature affect remarkably on the separation. The optimized separation condition is 1.4cm×17.5cm resin bed with 25mg of Er³⁺ load, temperature higher than 25℃, and pH=4.00 and pH=4.05 as fluent pH of Yb³⁺ and Tm³⁺, separately. Under the optimized condition, the recovery of Tm is higher than 95%, and the decontamination factors of Tm³⁺ to Yb³⁺ and Er³⁺ are higher than 1000.