The Keggin ⅡB element-monosubstitiuted heteropoly compounds with the stoichiometry of K7［BW11O39M(H2O)］ (M=Zn, Cd) were prepared by one-pot method and characterizated via elemental analyses, FTIR, UV and XRD. The photocatalytic activity of K7［BW11O39M(H2O)］ was tested vis degradation of the model molecule, methyl red (MR). After 60 min irradiation in the presence of K7［BW11O39M(H2O)］ (20 mg·L-1), the degradation rate of an aqueous MR (25 μmol·L-1, pH 2) got to 95%.