Abstract: A oil bearing formation,15m thick,is first revealed in Miocene Suweiyi Formation of Neogene in Sha No.15 well of the northern Tarim basin,with core data obtained.It is a new discovery again on Yakela structure after Palaeozoic and Mesozoic oil-gas accumulations were recognized.In this paper,the explorative process of this formation and its significance as well as suggetions on the future work are also presented.