Abstract:Arsenic, a highly toxic metalloid, widely exists in the natural environment. Plants (especially wetland plants) can easily absorb and accumulate arsenic from the soil environment. Arsenic accumulated by plants is tranfered to animals along the food chain, and threatens human health. In addition to the physical and chemical properties of the soil, the biological transformation of arsenic in the soil heavily affects the bioavailability and fate of arsenic in soils. It has been found that dissimilatory arsenate(As(V))-respiring reduction, cytoplasmic As(V) reduction, arsenite (As(III)) oxidation, As(III) methylation, and organoarsenic demethylation play important roles in biogeochemical processes of arsenic in soils. With the development of analytical chemistry and molecular biology, some recent studies have found that soil organisms are also involved in the synthesis of organoarsenic, such as arsenosuagrs, arsenosugar phospholipids, arsenobetaine, arsinothricin, and thio-arsenic. Trivalent monomethylarsenic MAs(III) and arsinothricin can be used as primordial antibiotics. However, the synthesis mechanism and ecological functions of organoarsenics need to be further investigated. In this paper, four co-selective resistance mechanisms of microorganisms to both of antibiotics and heavy metals via the evolution were introduced in details: co-resistance, cross-resistance, co-regulation and biofilm induction. In particular, a new research direction of coupling arsenic pollution with antibiotic resistance in soil was put forward.. In the end, the future directions of arsenic biotransformation and co-resistance mechanism to arsenic and antibiotic were prospected.