Abstract: In the present paper, extraction characteristics of N,N,N’,N’-tetraoctyl diglycolamide (TODGA) and N,N-dihexyl-octamide(DHOA), for Am(Ⅲ) and some trivalent lanthanides from nitric acid solutions were studied. The effects of extractant concentration in n-dodecane, metal ions concentration, acidity of the aqueous phase, ionic strength of salting out agent and temperature on distribution ratios were examined. The results show that the distributions of Am(Ⅲ) and some trivalent lanthanides increase remarkably with increasing the concentration of TODGA, HNO₃ and NaNO₃, Am(Ⅲ) and some trivalent lanthanides are hardly extracted by DHOA. After adding DHOA to TODGA/dodecane system, the distribution ratios of Am(Ⅲ) and trivalent lanthanides decrease with increasing of the concentration of DHOA, but the distribution ratios are large enough for their recovery from HNO₃. The extraction distribution ratios of trivalent lanthanides with TODGA increase with increasing atomic number of them in conditions of our experiments. The enthalpy change, the entropy change and Gibbs energy change are obtained at 298.15K. The composition of the extracted species and the mechanism of extraction are also studied, and the extraction equation of Am(Ⅲ) and trivalent lanthanides by TODGA is deduced as follows: M³⁺_aq+3NO^-_3，aq+3TODGA_org→M(NO₃)₃•3TODGA_org