Abstract: The reductive back extraction behavior of Pu(Ⅳ) in the simulated 1BF with N,N di methylhydroxylamine (DMHAN) is systematically investigated under conditions of various contacting time,different concentrations of reductant,different concentrations of nitric acid and series of temperatures.It is found that the higher reductant concentration,the lower acidity and the higher temperature,the higher back extraction rate of Pu(Ⅳ) is acquired.This fact is in good agreement with the reduction of Pu(Ⅳ) with DMHAN in aqueous solution.During a short contacting time (<2 min),concentration of reductant,concentration of nitric acid and temperature play important roles in the back extraction rate of Pu(Ⅳ). After contacting the two phases over 2 min,they do not increase the stripping rate obviously.A computer program is developed to simulate the behavior of DMHAN stripping Pu(Ⅳ) in 30 % TBP/OK and its calculated results are in good agreement with the experimental results.