Deionized water and 3.5%NaCl were used to simulate the gentle and harsh corrosion environments respectively in this work.The atmospheric corrosion behavior of weathering steel in different corrosion orders was compared by alternative corrosion tests.The results of SEM and EIS of the rusted samples revealed that there was no compact rust layer formed in only gentle or harsh corrosion environment,while a compact rust layer formed after alternative corrosion in gentle and harsh environments.Corrosion mass gain results show that when corrosion started in the harsh environment followed by in the gentle environment,the formation of a compact rust layer needed less time than that in the opposite corrosion order.