Abstract: Iron-based materials as high-quality additives can significantly improve the reaction efficiency and system stability of anaerobic fermentation, and are considered to be one of the best treatments to solve the problems of unstable anaerobic fermentation operation and low methane yield. This study describes the effects of different iron materials on anaerobic fermentation, and explores the potentiation and inhibition effects of iron materials in different stages of anaerobic fermentation, as well as their applications in the supplementation of trace elements and the removal of pollutants. The results show that the iron-based materials can improve the methane production and system stability of anaerobic fermentation by lowering the oxidation-reduction potential (ORP), promoting the conversion of organic matter, enhancing the activities of key enzymes and direct interspecies electron transfer (DIET), and optimising the microbial community. However, the dilemmas of the iron-based materials dosage such as the high preparation cost, the ease of agglomeration, the low utilisation rate, and the low recycling rate limit the enhanced potential of the iron-based materials. Furthermore, the study discusses the mechanism of the combined effect of iron-based materials and other materials on improving the agglomeration effect or increasing the utilisation rate, and puts forward future directions of optimising the structure of composite materials to promote the utilisation rate and the recovery rate, which can provide theoretical support for the realisation of the engineered application of iron-based materials to enhance the anaerobic fermentation.