Abstract: Coring at weak formation usually uses pin hang in gcoring barrel, but when put it down to hole, it is constantly lose effective. Developed a new hanging structure of coring-ball hanging, the weight of its inner barrel act on ball rather than pin. The carry capacity of ball is well and can avoid release inner barrel in advance, enhanced success rat of coring. At the same time, the structure and its experiments of this coring tools are also introduced. The testing of this tool have confirmed it is useful for coring.