Abstract: Abstract: Phosphine (PH3) has been the most popular fumigant in use for pest control during the disinfestation of dry plant products. Since the PH3 is a colorless, flammable, and very toxic gas with a fishy or garlic smell, it is necessary to monitor the PH3 emission in a granary after fumigation. The Non-Thermal Plasma (NTP) combined with some catalysts has been widely expected to serve as a promising technique to detect Volatile Organic Gases (VOCs). However, there is little research about the NTP coupled iron oxide catalyst to remove the PH3 contaminant. In this study, a systematic investigation was made to clarify the effects of NTP combined with Fe2O3 catalysts on the PH3 removal efficiency using a dielectric barrier discharge NTP combined with a catalyst reaction device. The microstructure of catalysts after the coupling reaction was characterized by the Brunauer-Emmett-Teller (BET), X-ray powder Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The products and reaction mechanism were analyzed after removing PH3. The results showed that the NTP combined with the carriers and catalysts changed the discharge state for the higher removal efficiency of PH3. Once the input power exceeded 53 W, the removal efficiencies of PH3 by the NTP combined with Fe2O3 catalysts were much higher than that with the plasma alone. Furthermore, the Fe2O3/Al2O3 catalysts presented the best coupling effect during the removal of PH3 contaminant. Once the input power was 58 W, the removal efficiencies of plasma alone, Al2O3, and Fe2O3/Al2O3 were 29%, 31.29%, 100%, respectively. More importantly, the specific surface area of Fe2O3/Al2O3 catalyst decreased by 11.23% after the coupling reaction, the content of Fe3+/(Fe2++Fe3+) increased by 21.06%, the content of Osur/(Olatt+Osur+Oads) decreased by 2.24%, the content of Fe decreased by 4.69%, and the content of P increased by 4.34 times. Moreover, phosphoric acid was the main product during the treatment. The high-energy electrons and active substances produced by NTP were directly reacted with PH3, and also acted on the Fe2O3 catalyst, leading to the change of discharge state. Further, the REDOX reaction of Fe3+ was participated to produce more surface reactive oxygen species, so that the PH3 adsorbed on the surface of the catalysts was oxidized into the phosphoric acid, indicating a higher removal efficiency of PH3. Consequently, the NTP combined with Fe2O3/Al2O3 catalyst better performed the PH3 removal efficiency. The finding can provide a strong theoretical basis to remove the phosphine contaminant from the grain storage industry.