The prepared iron silicate was characterized using X-ray diffraction (XRD) and Fourier transformation infrared (FT-IR). The characterization studies showed that the Fe-O-Si bond is formed on the surface of the amorphous iron silicate which contains abundant functional groups. Iron silicate was used as an ozonation catalyst, and it showed significant activity in the decomposition of ozone in aqueous solution. The catalytic ozonation removal effectiveness of p-chloronitrobenzene (pCNB) pCNB was investigated under various physicochemical conditions. Both the adsorption and the single ozonation were not effective for the degradation of pCNB, but the presence of iron silicate in ozonation process could substantially enhance the pCNB removal efficiency. The hydroxyl radical scavenger experiment confirmed that iron silicate catalytic ozonation followed a radical-type mechanism. Better process removal efficiency should be at neutral pH than that at acidic pH or alkaline pH. It is concluded that the iron silicate was an efficient catalyst for pCNB degradation in aqueous solution.