The photoacouslic spcctra(PAS) of ternary complexes EuPhen2Sal3and TbPhen2Sal3are reported. Compared with the PA spectra of binary complexes, the change of PA relative intensities of salicylic acid(Sal) in ternary complexes indicates the different probabilities of nonradiative transitions and different relaxation processes. Combined with emission spectra the relaxation and energy transfer processes especially the interaction between two ligands are discussed.