The solvent extraction behavior of 224Ra was studied at pH5 using a 0. 1 mol/L solution of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) in benzene. It was found that the extraction of 224Ra was not sufficiently effective under such a condition. If small amount of TBP was added into the solution of PMBP-benzene the extraction efficiency of 224Ra increases considerably. It demonstrates that TBP has strong synergistic extraction effect for radium. The experimental data on the effect of the equilibrium time on the extraction of 224Ra in the extraction and striping as well as the dependence of 224Ra percept extraction on amount of TBP were obtained.