Abstract: Sandy conglomerate reservoir is characterized by mixed rock grains, strong heterogeneity and complex pore structures. Waterflooding in the sandy conglomerate reservoirs in Karamay oilfield encounters some problems such as water channeling and watered out, high overall watercut and low recovery factor etc., so indoor experiment and evaluation should be carried out for the sandy conglomerate reservoirs to provide guidance for reasonably making development scheme. This paper takes the sandy conglomerate reservoir in T2k1 of Karamay formation in District Qidong-1, Karamay oilfield as the research object, describes the characteristics of different pore structures in the reservoir on the basis of mercury injection and casting thin section analysis. Some typical cores are selected for waterflooding and polymer flooding experiments. Oil displacement efficiency and oil producing rule during displacement process and residual oil distribution after polymer flooding are determined by NMR. The results show that big differences among different types of pore structures result in different polymer flooding potentials, the highest oil displacement efficiency is obtained in Type Ⅱ pore structures; the highest oil producing degree by waterflooding is observed in the pore throats with the radius larger than 10.0 μm. The effective pore throat radius ranges from 1.0 to 10.0 μm for polymer flooding. The pores with the pore throat radius less than 1.0 μm make the lowest contribution for polymer flooding and the oil displacement efficiency of polymer flooding can be improved by 13.09% on average