An empirical distribution ratio model for Am and fission product lanthanides (FPLn) in HBTMPDTP extraction and a method of process parameter calculation are presented. A conceptual process flow sheet for Am/FPLn separation by HBTMPDTP extraction is proposed. The decontamination factor of Am from FPLn is higher than 106, and the coextraction of FPLn together with Am is <0.15% with five extraction stages.