Many clay molds, which were used to cast metal molds for minting bronze coins have been excavated from Han Dynasty mint sites in Shaanxi province,. We can understand not only how ancient craftsmen used a clay mold to cast a metal mold, but also how a metal mold was used to cast bronze coins in the Han dynasty. The change in clay mold structures used for casting metal molds in the Han dynasty is presented in this paper. There were three kinds of pouring gates in the clay molds. Most clay molds were made of two layers:a facing mold and a backing mold. Some clay mold remains from Xiangjiaxiang and Wotouzhai minting sites were analyzed. The compositions of five clay molds analyzed by XRF showed no identical difference between the facing and backing materials. The twolayer mold was used so that a clearer cavity surface could be made from a model. The compositions of cavity surface and noncavity surface of one of the facing molds (Xiaoquanzhiyi No.2) was studied by Electron Probe analysis, but it could not be determined whether or not any coating was applied to the cavity surface, suggesting that this mold was used to cast an iron mold, which could be another important type of metal mold used during the Han dynasty.