Diamides and phosphine oxides having many types of central frames were synthesized and employed in order to determine the behavior of the actinides (An)(III), (IV), (V) and ( Measurement of the D value at different extractant concentrations gave information on the extraction reaction and extraction ability. From the present work, the best extractant is BDPPM, due to the strong affinity provided P=O group and its bidentate form resulting in six-membered ring chelation. However, this extractant has too low a solubility in n-dodecane. From the properties required for application, e.g., high solubility in n-dodecane, easy organic synthesis, gasification by combustion and high actinide extractability, into consideration, diglycolamide (DGA) is a promising extractant for radioactive waste treatment.