Abstract: The following extractants were examined for the extraction of Cf and Cm from HNO3 medium: di (2-ethylhexyl) phosphoric acid (HDEHP), 1-methylheptyl phenylphosphonic acid (HMeHΦP), 2-ethylhexyl phenylphosphonic acid (HEHΦP), di (isobutylmethyl) phenylphosphonic acid (HDIBMeΦP) and 1-methylheptylisoalkylphosphonic acid (HMeHIRP). The extraction properties of HMeHOPand HDEHP were further compared. The results show that HMeHΦP is the better extractant for the extraction and separation of Cf and Cm. The distribution coefficients (K) with these two extractants are directly proportional to approximately second power of extractant concentration and inversely proportional to approximately third power of the nitric acid concentration in aqueous phase under the same conditions, and K and separation factors (SF) with HMeH ΦP are greater than those with HDEHP. When cations such as Na+, Al3+ and Pd2+ exist in aqeous phase, Kcf, Kcm and SF slightly decrease. Satisfactory decontamination factors are found for 137Cs and 106Ru, but those for 95Zr-95Nb, 144Ce and 152,154Eu are not good.