Although many underwater superoleophobic surfaces for separating immiscible oil/water mixtures have been constructed, the fabrication process of most of surfaces is non-green, complex, and time-consuming. Herein, a novel underwater superoleophobic stainless steel mesh (SSM) with eco-friendly coating was successfully prepared by simple and rapid one-step liquid phase chemical reduction route. The reduction treatment produces the iron (Fe) coating with micro/nano-structure, resulting in the underwater superoleophobicity, with oil contact angle as high as 152 degrees. Such special wettability makes the surface to be readily wetted by water phase while repelling immiscible oil phase simultaneously. For this, the effective separation (separation efficiency: > 96.2%) of oil/room temperature water and oil/hot (90 degrees C) water mixtures can be achieved by the decorated mesh. Specially, oil/hot corrosive water mixed liquid can be efficiently separated, and the mesh still maintains good separation efficiency (> 94.6%) even after 30 cycles of separation. This research work provides a green, facile, and cost-effective strategy to construct the coating for oil/water filtration on metal mesh. It is expected that the as-fabricated mesh can be used as the filtration material for oily wastewater purification and oil spill treatment.