The spectral properties of Cr

3+

doped calcium aluminium germanate garnet (Ca

3

Al

2

Ge

3

O

12

) have been investigated. Dependence of the zero-phonon-line positions from Cr

3+

in the inequivalent crystallographic sites has been studied as a function of concentration and temperature. The crystal field intensity parameters

D

q and Racah parameters were deviated by analyzing the absorption and emission spectra. The fine structure of Cr

3+

in Ca

3

Al

2

Ge

3

O

12

at low temperature has been assigned as a vibronic progression in two kinds of phonon with energies ω

1

(A)=165～170cm

-1

ω

2

(A)=200cm

-1

and ω

1

(B)=130～135cm

-1

ω

2

(B)=185～190cm

-1

. The luminescence decay behavior of Cr

3+

different transitions has been investigated upon red laser excitation and showing single exponential decay curves.