In this article, cesium ions were introduced into the FeCo Prussian blue analogues (PBA) catalyst to increase the styrene conversion and the selectivity in styrene oxide in the reaction of epoxidation of styrene. The conversion of styrene over CsFeCoPBA-1 on the optimal condition reach up to 96%, in comparison to 88% over FeCoPBA. The catalysts were characterized by fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), thermogravimetric analysis (TG) and N-2 adsorption/desorption, respectively. To further illustrate the phenonmen, the detailed kinetic studies on epoxidation of styrene were carried out. It is found that the rate equations is similar between the catalyst CsFeCoPBA-1 and FeCoPBA, while the reaction activation energy with CsFeCoPBA-1 catalyst is reduced obviously. Meanwhile, isothermal titration calorimetry (ITC) had also been employed to directly probe thermodynamic changes during the formation of the PBA with or without Cs ions. It is noteworthy that higher enthalpy change in the presence of cesium ions.