There are many kinds of expanding mould, and rubber punch is more than others. Of course there are many hydraulic pressure mould, but there are a litter of which can be multipurpose and be suit for many kinds of products. Through researching some kinds of products, using of a kind of called Half structure and a common use of die set, a kind of no punch hollow part hydraulic pressure expand mould was designed. In this kind of mould, the product can be separated from the mould and be reset easily, and only the cavity size should be designed because of the outer size of mould never be designed. It has a fixed size and structure. The punch was made of rubber capsule, when product was needed to expand, the hydraulic pressure oil was supplied by the oil pump. When the product was needed separated from the mould, the oil in rubber capsule should be taken out of it at first, then the Half structure may be ejected, at the return trip, a T shaped pole was used to reset. This mould was of simple in structure, and the action was reliable and very practical.