At present，Saertu oilfield is at high water cut stage and it is necessary to identify the distribution of its remaining oil. And analytical method of sealed coring well is the most intuitive and reliable one. Based on reservoir subdivision，the overall water-flooding characteristics of the main blocks and different reservoirs were analyzed according to the waterflooding characteristics of four new sealed coring wells drilled in Beierxi area of Saertu oilfield. The results show that the overall water-flooding characteristics of the reservoirs in this area are at medium degree，which indicates a great potential of the block. The water-flooding degree of the main part of channel sand is higher：primarily medium and strong. The medium and strong waterflooding mainly distributes in the middle of channel sand and the weak and non-waterflooding is on the top of channel sand. The overall water-flooding degree of the tabulated reservoir is medium and that of the untabulated reservoir is quite low. The weak and non-waterflooding distributes in the thin-layer tabulated reservoir and isolated untabulated reservoir. It indicates that the potential reservoirs mainly locate on the top of the channel sand，the middle of the channel sand，the thin-layer tabulated reservoir and isolated untabulated reservoir，which are the targets of adjustment and potential tapping in the future.