Abstract: A multistage countercurrent extraction process is developed for the removaland recovery of actinides and lanthanides by 30(V)% bidentate organophospho-rous extractant DHDECMP in diethyl benzene from 3 mol/1 nitric acid solutionof simulated nuclear power reactor fuel reprocessing waste. In the R-A extractioncycle (6 extraction stages and 2 scrub stages), the recovery efficiency for U, Np,Pu, Am and Gd is 99.95%, 99.40%, 99.95%, 99.99% and 99.70% respectively,and the decontamination factor for fission product elements is DF_(Zr)>3.6×10~3,DF_(Nb)>3.7×10~3, DF_(Ru)=6.8, DF_(C?)>3.9×10~3 and DF_(Sr)>2.8×10~3 respectively.In the R-B cycle (6 stripping stages) for the stripping of Pu, Am and Gd fromorganic phase, the stripping efficiency for Pu, Am and Gd is 96.58%,>99.65%and>99.70% respectively. Finally, in the R-C cycle (6 stripping stages) for thestripping of Np and U, the stripping efficiency for Np is 99.95% whereas thatfor U is 98.02%.