The bunch casting technique,which utilized two molds and the cavities laid out symmetrically side by side on both sides of the sprue,was the first one to be used for casting bronze coins in China.The molding material could be stone,clay or metal.But most molds were metal or stone. Because only a few clay molds for casting coins have been found in China,it has not been a focus of research until now. The surviving Han Dynasty relics related to clay mold bunch casting are classified and analyzed in this paper.This technique was used not only in the early Han Dynasty,but also to cast bronze coins up to the time of the Eastern Han Dynasty.Base on experimental castings made in laboratory,the Han Dynasty clay mold bunch casting process can be described as follows. First,a model was made.This could be a metal model cast in a two part clay mold.Second,clay molds were made from the model.Third,after baking the molds,the molten bronze was poured into the mold's cavity to form bronze coins.Clay molds could be made with great efficiency by using a metal model.A metal model also could guarantee metal coins with consistent size and characters.