Abstract: A certain amount of liquid in the core sample may be lost in the process of sealed coring and saturation testing, which may result in deviation between the oil and water saturation measured with these in-situ. There is some irrationality in the traditional saturation correction in which the loss of oil and water is considered to be equal. The authors tried a new method in the process of saturation correction of sealed coring samples from Well Y to eliminate the deviation. First step, put the cores that have been measured by distillation saturation test into a long core; Second step, conduct the water flooding simulation under the stimulated formation condition and then the distillation saturation test under surface condition; Third step, calibrate the lost percentage of oil and water saturation and then correct saturation test data of sealed coring from Well Y. Compared with the interpretation results of logging data, it shows that the results corrected by water flooding experiment of long core are precise and faithful, and are helpful to identify the water-flooded zone in the oil field and set out the adjustment strategy of development wells.