Abstract: On the basis of analyzing the well logs and core data , the characteristics of the rock & electric property of 139 wells in this area have been analyzed.The fine stratigraphic classification and correlation in Chang-8 reservoir of Yanchang formation in X area of Jiyuan oilfield has been completed.From top to bottom , Chang-8 can be divided into Chang 811 , Chang 812 , Chang 821 and Chang 822 , and the thickness in every tiny stratum is different.Among them , Chang 811 and Chang 821 are underwater distributary channel deposits , and with abundant sand bodies , they became the dominant reservoir in X area of Jiyuan oilfield.The fine stratigraphic classification and correlation of Chang-8 reservoir can provide geologic basic data for study on sand body distribution , sedimentary microfacies during the development stage.In short , the fine stratigraphic classification and correlation of Chang-8 reservoir has a deep significance on oilfield development.