The fluorescence spectrum and lifetime of SrTiO3:Cr3+ crystal were measured from 5K to 200K. The variation of lifetime as the temperature below 150K was well explained by the theory involved in the processes of emission and absorption of single phonon. Defects of charge compensation were considered as the main reason for the quenching of fluorescence at high temperature and the relative model of the energy transfer was built. Besides, the violet shift of R-line as the rise of temperature was discovered and explained by crystal-field and covalency bond theories reasonably. Some important spectral parameters, such as Huang-rhys factor, R-line oscillator intensity and corss section, were obtained.