A macroporous silica-based octyl(phenyl)-N,N-diisobutylcarbamoylmethylphoshine oxide (CMPO) chelating polymeric Composite, CMPO/SiO2-P, was synthesized by impregnating and immobilizing CMPO into the pores of SiO2-P particles support. To separate long-lived minor actinide (MA(III)) elements such as Am(III) and Cm(III) from highly active liquid waste (HLW), the adsorption and elution of 13 representative simulated fission products from a 3.0 M HNO3 were performed. It was carried out through two columns, both packed with CMPO/SiO2-P at 323 K. In the first column, all of the simulated elements were separated into three groups: (1) Cs(I), Sr(II), and a portion of Ru(III) (nonadsorption group); (2) Pd(II), a portion of Zr(IV), and all of REs(III) (MA-RE-Pd-Zr group); and (3) most of Zr(IV), Mo(VI), and a portion of Ru(III) (FPs group) by eluting with 3.0 M HNO3, H2O, and 0.5 M H2C2O4, respectively. MA(III) were predicted to flow into the second group along with Gd(III) because of their close adsorption and elution behaviors onto CMPO/SiO2-P. By addition of 0.5 M DTPA and conditioning of the HNO3 concentration to 3.0 M, the MA(III)-containing effluent was then supplied to the second column and separated into (1) Pd(II), (2) RE(III) elements Sm(III), Eu(III), Gd(III), and Y(III) (MA-RE group), and (3) Zr(IV) by eluting with 3.0 M HNO3, H2O, and 0.5 M H2C2O4, respectively. MA(III) flowed into the MA-RE group along with Gd(III). Based on the position of MA(III) in the elution curves, an effective group partitioning process of MA(III) and RE(III) from HLW by extraction chromatography was proposed.