The sample preparation is a process required in AMS 14C dating. It is very important to choose appropriate chemical pretreatment for different sample. The carbon dioxide gases are produced by combusting pretreated organic samples with CuO in a sealed quartz tube. Graphite targets are prepared via the reduction of carbon dioxide over a Fe catalyst and a Zn reducer. The sample preparation have succeeded in a vacuum system mainly in order to reduce the amount of comtamination