Abstract: ith the prominent advantages of super sensitivity,small sample and high tbroughput,AMS has been developed rapidly during the past two decades in the world. Its application covers a large variety of fields including earth science,archaeology,physics,environment,material and biological science. Peking University Accelerator Mass Spectrometry(PKUAMS)facility was established in 1991 and has been put into routine 14C measurement since May, 1993. Since then over 650 samples in diverse application fields have been measured and a series of valuable achievements have been gotten. In this paper we ihtroduce the facility systematically and present the methods of 14C measurement in detail.