The ultrafast dynamics of the luminescence enhancement in [Ru(dmb)2(mitatp)]2+ and [Ru(dmb)2(mitatp)]2+/DNA complex has been studied by use of time-resolved luminescence spectroscopy. The transient luminescence relaxation processes of [Ru(dmb)2(mitatp)]2+ and [Ru(dmb)2(mitatp)]2+/DNA complex have been measured with comparison method. The luminescence is due to the transition between charge transfer singlet and triplet states. The results show that after interaction with DNA, the lifetimes of fluorescence and phosphorescence of [Ru(dmb)2(mitatp)]2+ complex are prolonged from 339 ns to 589 ns and from 16 μs respectively, and the total luminescence intensity is enhanced by one order of magnitude. The possible origin may be the formation of the new energy levels of the photoexcited charge-transfer singlet and triplet states by the interaction between [Ru(dmb)2(mitatp)]2+ and DNA resulting in the decrease of the nonradiative decay rate from the lowest excited state to the ground state and the increase of the luminescence efficiency.