Abstract: A new approach for determining the remaining oil distribution in single layer was put forward in view of the various controlling factors, the discrete distribution and the difficulty in discrimination of remaining oil in nonmarine mature developed reservoir. Four controlling factors of remaining oil distribution, which include structure, heterogeneity, well pattern and water flood behavior of reservoir, were applied to build a fuzzy mathematic model. The degrees of attribution of all the controlling factors were calibrated by the production performance of single layer wells, the log interpretation of the new drilled wells and the remaining oil saturation monitoring wells. The comprehensive evaluation indexes of individual well points can be obtained to quantitatively characterize the distribution of remaining oil through the fuzzy calculation. The 11 layer, member 2 of the Shahejie Formation in segment 1 of Shengtuo oilfield was taken as an example. It belongs to fluvial reservoir and has been exploited for more than 40 years. The distribution model of comprehensive evaluation indexes was built up, which guilds the development and stimulation treatment satisfactorily.