The natural enrichment of arsenic(As) in the shallow groundwater of Jianghan Plain, central Yangtze River Basin, has been reported. Many studies have showed the processes related to arsenate reduction, iron reduction can be involved in As release. However, the biogeochemical process of sulfate reduction in the high As aquifers is not clearly understood yet. According to the field groundwater investigation in Jianghan Plain, the high As(2550 μg/L) and low Fe(II)(1.5 mg/L) concentration were observed in shallow groundwater. However, previous studies indicated the As concentration showed positive correlation with iron concentration, which is related to the reductive dissolution of As-bearing iron oxides. Therefore, the microbially mediated sulfate reduction, as one key link in the redox sequence, may be equally important for the As mobilization in the groundwater, but this hypothesis remains to be tested. The purposes of this study were to 1) identify the effects of microbially mediated sulfate reduction process on the As mobilization and transformation; 2) discriminate the predominant process responsible for As mobility in high As aquifers with hydrogeochemical characteristics of high As and low Fe(II). We used the sediment samples collected from the monitoring well(YLW03) with high As and low Fe(II) in shallow aquifer at the depth of 20.75 m to design the 75-day incubation experiments under anaerobic condition. The results indicated that the intense sulfate reduction could indirectly promote As/Fe(II) release from sediments, which increased to 255.70 μg/L/3.53 mg/L, 285.00 μg/L/5.99 mg/L respectively in the microcosms with acetate amended and no amendment along with the functional gene(dsrB) copies increasing to 1.11×10⁵/6.34×10⁵ obviously. The sulfate reduction could also promote arsenate reduction along with the increase of arrA copies. In addition, the microbially mediated sulfate reduction also contributed to form thio-As (H₂AsS₄^-), which could promote As release further. Initially, along with the relative abundance of sulfate-reducing bacteria(SRB) including Desulfomicrobium increasing to 26.87%/30.58%, As released via the formation of sulfide, which could reduce the amorphous iron-oxides indirecty. Although the Fe-sulfide minerals formed simultaneously, they could not consistently inhibit the mobilization of arsenic. After 14 days of incubation, the relative abundance of iron-reducing bacteria(FeRB) including Geobacter increasing to maximum, 10.53%/16.70%, which could contributed to the poorly crystallized Fe-sulfide minerals and amorphous iron-oxides translating into pyrite and crystallized iron-oxides via iron reduction. Although a fraction of As was immobilized transiently, the As released into the liquid phase again then with the Fe(II) is scavenged finally. At the end of incubation, methanogens became predominant, which indicated the evolution of microbial community. According to those results, sulfate reduction play an important role on As mobilization and transformation in weakly alkaline groundwater. The sulfate reduction in in situ environment requires long-time investigation to better understand the sulfide-based immobilization strategies.