Manganese molybdates MnMoO4?xH2O (x=0.9,1.5) could be obtained by the method of a microemulsion based on a quaternary system（CTAB/ water / pentane / isoamyl alcohol) under different manganese precursors. According to XRD , the DSC and TG traces, it was proved that MnMoO4?0.9H2O could be prepared under the precursor manganese of MnCl2?4H2O, and the other precursor manganese of C4H6MnO4?4H2O was MnMoO4?1.5H2O. And it was showed that ω([CTAB]/[H2O]) and the different manganese precursors had great influence of the microstructure of the final product. It could be well known from the solid ultraviolet spectra that the band-gap energy of MnMoO4?0.9H2O could reach up to 3.08eV, and MnMoO4?1.5H2O was 3.04eV.