Abstract: During gamma irradiation of the system TBP-DBBP, energy of certain excited state of TBP can be transferred to DBBP. The protective effects on TBP, afforded by DBBP and by H2O, are just the same. The accepted energy from excited TBP may cause the excitation of DBBP at the P = O bond. This amounts to about 29% of the total excited and ionic state of TBP, which form DBP.While receiving the excited energy from TBP, DBBP itself is "sacrificed". We have applied steady state theory to study the kinetics of energy transfer of the system TBP-DBBP,and derived the equation of sensitization of DBBP. Theoretical values agree well with the experimental results.