In order to determine the corrosion products of the late Warring States Period iron wares unearthed from the City Site of Zheng and Han States (Zheng Han Gucheng), 13 iron samples with corrosion products were studied using a variety of methods including X-ray diffraction (XRD) and metallographic microscopy. The results indicate complicated mechanisms, diverse components and obvious stratification of the corrosion products. Some iron wares also contain active corrosion products. This study also indicates that preservation states of iron wares have a close relationship with their metallographic structures.