In this paper, the absorption and Fluorescence spectra of Cr4+,Nd3+: GGG (Cr,Nd:GGG) crystal, Nd: GGG crystal and Cr4+: GGG crystal are reported. In the absorption spectra there are big absorption bands at 400 and 520nm, which correspond to the 4A2→4T1 and 4A2→4T2 transitions. The luminescent spectra of Cr,Nd:GGG and Nd:GGG show that the luminescent center of Cr,Nd:GGG is at 1.062um, but the intensity is 6 times lower than that of Nd:GGG. The luminescent lifetimes of Cr,Nd:GGG is shorter than that of Nd:GGG. These may be caused by the existence of ground state absorption of Cr4+ which quenches the Nd3+ emission intensity. These Cr,Nd:GGG crystals may be potential materials for compact, efficient, high stability diode- laser-pumped passive Q-switched solid state laser.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.