The Raman spectra of low-pressure and high-pressure Ca2AlSiO5.5 oxygen-deficient perovskites have been investigated in the temperature range of 153-1273 K at ambient pressure. No phase transition was observed for low-pressure Ca2AlSiO5.5 in this study, but an irreversible phase transition was observed for high-pressure Ca2AlSiO5.5 at 1223 K. The recovered sample of high-pressure Ca2AlSiO5.5 from 1273 K was confirmed as a single homogeneous phase (high-temperature Ca2AlSiO5.5). The Raman spectra of high-temperature Ca2AlSiO5.5 phase have also been studied in the temperature range of 153-1273 K at ambient pressure. All the observed Raman active bands of the three samples showed linear temperature dependence with different slopes. The quantitative temperature dependences of Raman bands are -2.90 x 10(-2) (similar to) -0.31 x 10(-2), -3.56 x 10(-2) (similar to) -0.50 x 10(-2), and -3.20 x 10(-2) (similar to) 0.28 x 10(-2) cm(-1) K-1 for low-pressure, high-pressure and high-temperature Ca2AlSiO5.5, respectively. The isobaric mode Gruneisen parameters of low-pressure Ca2AlSiO5.5 were calculated by using present high-temperature Raman spectra combined with a previous result of the thermal expansion coefficient, varying from 0.08 to 1.10 with an average of 0.35.