Polyacrylonitrile-thiosemicarbazide resin (PAN-TSC) bearing a triazolthione functional group was synthesized from crosslinked polyacrylonitrile and thiosemicarbazide. The functional group capacity and percentage conversion of the functional group of PAN-TSC prepared under optimum conditions were 4.39 mmol FG/g and 39.04%, respectively. The structure of PAN-TSC was confirmed by LR, elemental analysis, and X-ray photoelectron spectroscopy (XPS). The sorption capacities of PAN-TSC for Rh(III), Ru(IV), Pd(II), and Ir(TV) were 82.7, 239.7, 430.8, and 417.0 mg/g resin, respectively. The distribution coefficients were 1.30 x 10(4)-4.07 x 10(5) (ml/g). PAN-TSC resin has excellent sorption selectivity for Rh(III), Ru(IV) and Ir(IV) in the presence of common metal ions over a wide acidity range. The apparent activation energy (E-a) of sorption of PAN-TSC for Ru(IV) is 43 +/- 4 kJ/mol. The sorption mechanism of PAN-TSC resin for Ru(TV) was confirmed by XPS.