Abstract: The surface of fly ash was modified using an alkali fusion-acid washing method to prepare an active Si-Al carrier. And Fe, Ce, La composite oxides were used as the active components to prepare FeCeLaO/active Si-Al carrier composite adsorbent by co-precipitation method. The adsorbents were characterized by X-ray fluorescence spectroscopy (XRF), specific surface area measurements, and X-ray diffraction (XRD) patterns. Effects of temperature, Si/Al mass ratio, FeCeLaO loading ratio on arsenic removal efficiency and sulfur poisoning resistance of the composite adsorbent were investigated. Results show that the arsenic removal capacity of active Si-Al carrier increases first and then decreases with the increase of Si/Al mass ratio and adsorption temperature. The optimal Si/Al mass fraction ratio is 1.85, achieved a maximum arsenic removal efficiency of 78.7%, which is 2.8 times higher than that of raw fly ash. The highest removal efficiency of 84.8% is located in the high temperature range of 600 ℃. The best adsorption temperature of FeCeLaO/active Si-Al carrier composite adsorbent is located in the middle and low temperature section of 400 ℃, the arsenic removal efficiency is as high as 96.9%, and the best loading ratio of active components is 1∶1. The anti-sulfur poisoning ability of active Si-Al carriers is enhanced with the increase Si/Al mass fraction ratio. The introduction of FeCeLaO active component is conducive to the enhancement of the antisulfur poisoning ability of the adsorbent, and the higher the loading ratio, the stronger the anti-sulfur poisoning ability. The reason for the strong anti-sulfur poisoning ability of FeCeLaO/active Si-Al oxides is mainly due to the surface acidity of SiO₂ and the protective effect of elemental Ce on the active components, such as Fe, La, Al, etc.