Abstract: Based on the sedimentary microfacies analysis of key wells,the log characteristic parameters for all kinds of sedimentary microfacies have been extracted from the well log data integrating with well logging,geology and mathematics.The discriminant models for the sedimentary microfacies have been established by means of multivariate statistical analysis.We have succeeded to program a software,which could implement the automatic and continuous discrimination of sedimentary microfacies for the hole profile using well log data.The log data from more than ten wells of anonymous oilfield have been processed using the soft ware,and drawn the plane graph of sedimentary microfacies.