Quantitative description of sedimentary microfacies is an effective way to study reservoir. This paper selects natural gamma and spontaneous potential logging curve to use their  root-mean-square, skewness and the average amplitude between the upper and lower within bed limit to serve as indexes in quantitative identification of sedimentary microfacies. The average amplitude of logging curve is used to classify as small and medium curve. Data skewness within bed limit is used to be a quantitative parameter to determine the curve stability and shape, which is employed to identify the stable and unstable curves. The average range of the upper and lower amplitude within bed limit is used to further ensure the morphology of logging curve. By using this method,  many microfacies such as meandering stream channel, beach, crevasse splays, natural levees and flood plain, have been identified in meandering stream deposits of Shahejie formation, Qudi oilfield, which validates this method.