Abstract: Because of multilayer injection and commingled production in offshore oilfield,the oil and water distribution is complex,and there are many influencing factors on reservoir in the later period of high water cut,so it is difficult to identify the water out behavior of each layer.In order to save time and cost,a mul-tiple layers fuzzy comprehensive evaluation method was developed to analyze water out behavior in oil reser-voir based on sealed coring data. Six parameters for characterizing water out behavior were taken to estab-lish fuzzy matrix and weight coefficients of every parameter were determined.The synthetic index of water out behavior was built by weight average algorithm and further synthetic evaluation were made in terms of field test and observed rock core.This method was applied to well SZ36-1-B19 in Suizhong 36-1 oil field and ranking of water out behavior of those units were presented.