Abstract: The Chengdao Oil Field is the first shallow oil field put into development in China.Applying sedimentary petrography and geology,the sedimentary petrographical and structural characteristics,logging curves and palaeontologic features of the Neogene upper Guantao formation(Ng) have been studied on the basis of geological setting,core description and logging analysis.Sands of the upper Ng belong to fluvial facies and the subfacies is meandering river by many identification parameters of river types.Then,4 types of microfacies have been concluded,the palaeocurrent directions of the main unit have been pointed out,and the deve-lopment characteristics and effects of different microfacies have been evaluated.