In this paper, the spontaneous Raman spectra of K(H1-xDx)2PO4 (DKDP) crystals with different deuteration degrees in the Z(XX)Y scattering geometry are measured. And the Raman spectroscopy parameters including Raman shift, full-width at half maximum, and scattering intensity, which are related to the transverse stimulated Raman scattering (TSRS) gain coefficients, are analyzed in detail. Using the Raman scattering from water as a reference, the TSRS gain coefficients of DKDP crystals with different deuteration degrees are derived. It is found that with increasing deuteration degree in DKDP crystal the TSRS gain coefficient first decreases to about 40.1% of the KDP crystal, then increases to about 68.9%. We regard the change of the full-width at half maximum as the main reason for the dependence of TSRS gain coefficient on the deuteration degree.