Abstract: Sewage sludge and ultra-low concentration methane are typical solid wastes and greenhouse gases, posing urgent environmental and energy challenges due to their inefficient resource utilization. This study used red mud as an oxygen carrier, sewage sludge/coal powder as fuels, and ultra-low concentration methane as an oxidizing gas to systematically investigate the effects of temperature (800−950 °C), steam flow rate (0−0.2 g/min), and coal blending ratio (0−50%) on chemical looping gasification performance in a fluidized bed reactor. In addition, the crystalline structure and surface morphology of the oxygen carrier before and after reaction were analyzed. Results showed that under conditions of 900 °C, 0.1 g/min steam flow rate, and 40% coal blending ratio, the carbon conversion rate was 93.90%, with H₂ and CO yields of 45.58×10⁻³ and 7.75×10⁻³ mol/g, respectively. Furthermore, the CH₄ conversion rate exceeded 99% across all experimental conditions. Elevated temperatures enhanced carbon conversion and gas yields, but excessive temperatures reduced reactivity due to oxygen carrier sintering or ash fusion. Steam addition significantly improved carbon conversion and H₂ yield but suppressed CO production, while excessive steam lowered localized temperatures and inhibited the reaction. The co-gasification of sludge and coal exhibited a synergistic effect: volatile matter from sludge promotes coal char gasification, and the high fixed carbon content of coal compensates for the low calorific value of sludge, collectively enhancing gasification efficiency. XRD and SEM-EDS characterization revealed that the red mud oxygen carrier maintained stable Fe₂O₃ crystallinity despite post-reaction grain refinement, demonstrating excellent oxygen transport capacity and thermal stability. This study provided theoretical and experimental foundations for optimizing sludge/coal co-gasification technology and validated the feasibility of chemical looping processes for synergistic disposal of red mud, sewage sludge, and ultra-low concentration methane, offering innovative insights into waste-to-energy conversion.