Abstract: The effects of temperatures on the corrosion resistances and microstructures of 2205 stainless steels in different media were studied by box resistance furnace, metallographic microscope, electrochemical workstation and other equipments. The results show that as the solution temperature increases, the austenite content decreases and the ferrite content increases. In solutions of different p H values the corrosion resistances of duplex stainless steels were different. In acidic solution, when the solution treatment was carried out at about 1 050℃, the corrosion resistance was the best and the ratio of austenite content to ferrite content was 1:1; in alkaline solution, when the solution treatment was carried out at 1 100℃, the corrosion rate was the lowest; in Na Cl solution, when the solution treatment was carried out at 1 100℃, no obvious passive area appeared in the 2205 duplex stainless steel, but the corrosion rate was low and the corrosion resistance good.