Molybdaenum trixide MoO3 was accessed to replace some WO3/[WO4] in the NaY(WO4)(2) crystal. The undoped NaY(W0.8Mo0.2O4)(2) crystal was grown in nitrogen by using Czochralski method. The single crystal X-ray diffraction was performed, resulting in the appearance of some different structure between NaY(W(0.8)Wo(0.2)O(4))(2) and Nay(WO4)(2) crystals. And spectral properties especially their Raman spectra were discussed by detail. (c) 2007 Elsevier B.V. All rights reserved.