Ployacrylonitrile (PAN) nanofibers were formed by electrospinning. Amidoxime ployacrylonitrile (AOPAN) nanofibers were prepared by reaction with hydroxylamine hydrochloride, which were used as the matrix for metal ions chelation. FTIR spectra of the PAN nanofibers and AOPAN nanofibers were recorded for analysis of the surface chemical structures. The AOPAN conventional fibers were also prepared for comparison, and surface morphologies of the modified PAN conventional fibers and PAN nanofibers were observed by FESEM. Metal ions concentrations were calculated by AAS. The chelated isothermal process and kinetics parameters of the modified PAN nanofibers and PAN conventional fibers were studied in this work. Results indicated that the saturated coordinate capacity of AOPAN nanofibers to $Cu^{2+}$, $Cd^{2+}$ was 3.4482 and 4.5408 mmol/g (dry fiber) respectively, nearly two times higher than that of AOPAN conventional fibers. Besides, the desorption rate of $Cu^{2+}$ and $Cd^{2+}$ from metal chelated AOPAN nanofibers was 87 and 92 % respectively in 1 mol/l nitric acid solution for 60 min. The isothermal processes were found to be in conformity with Langmuir model.