The fluorescence spectra of Cr,Tm,Ho∶YAG crystal have been detected at the temperature from 65 to 295 K with interval of 10 K.The width and the shift of Ho3+ lines at 4959.6 cm-1 (at 65 K) have been investigated and interpreted in terms of the interactions between lattice vibration (phonons) and ions.The results showed that the line broadening with the temperature was mainly due to the Raman scattering of phonons,and the line shift with temperature was mainly due to the emission and absorption of virtual phonons.