In present paper, a method was developed to simulate offshore conditions for screening steel materials for marine application. The device used was described. By using the device, the raise and low levels of sea water can be controlled automatically, and waves can be brought about with a simple wave-making machine installed in the cement tank. The experiments were carried out in the tank with flowing sea water. Thus, in a 3 m3 tank different marine corrosion environments such as atmospheric zone,splash zone,tidal zone and submerged zone can simultaneously be shown as offshore. In addition a brief account was given to the long scale hanging specimens, the separate hanging specimens， and the hanging specimens connected electrically.