A series of trimetallic Prussian blue analogues (PBAs) has been synthesized by adding Fe or Cu to five types of bimetallic PBAs: FeCoPBA, CdCoPBA, CoCoPBA, MnCoPBA, and ZnCoPBA. Such compounds have been characterized by scanning electron microscopy, infrared spectroscopy, and X-ray diffraction measurement. They generally had smaller particle sizes and weaker diffraction peaks than the corresponding bimetallic PBAs. Then, supplementary characterizations on the CuZnCo PBA and CuCdCo PBA showed that the crystallization process, the specific surface area, and the acid sites of the trimetallic PBAs are all different from those of the corresponding bimetallic PBAs. Thermodynamic data obtained by isothermal titration calorimetry indicated that the synthesis of the CuZnCo PBA and CuCdCo PBA is a spontaneous exothermic process with values of enthalpy change in the same range as the corresponding bimetallic PBAs. Such compounds were used as heterogeneous catalysts for the epoxidation of styrene. The results revealed that the catalytic activity of the trimetallic PBA was more efficient than the one of the corresponding bimetallic PBA. Moreover, the experiment of reusability and stability shows that the CuCdCo PBA catalyst is pretty stable.