Growing environment problem and emphasis of environmental protection motivate intense research efforts in exploring technology to improve treatment efficiency on refractory organic pollutants. Hence, finding a method to make up for the deficiency of anaerobic digestion (AD) is very attractive and challenging tasks. The recent spark in the interest for the usage of some nanomaterials as an additive to strengthen AD system. The adoption of iron compounds can influence the performance and stability in AD system. However, different iron species and compounds can influence AD system in significantly different ways, both positive and negative. Therefore, strengthening mechanism, treatment efficiency, microbial community changes in Nanoscale Zero Valent Iron (nZVI) and Fe3O4 nanoparticles (Fe3O4 NPs) added AD systems were summarized by this review. The strengthening effects of nZVI and Fe3O4 NPs in different pollutants treatment system were analyzed. Previous study on the effects of nZVI and Fe3O4 NPs addition on AD have reported the concentration of nZVI and Fe3O4 NPs, and the types and biodegradability of pollutants might be the key factors that determine the direction and extent of effect in AD system. This review provides a summary on the nZVI and Fe3O4 NPs added AD system to establish experiment systems and conduct follow-up experiments in future study.