Abstract: At the late stage of oilfield development, due to the influence of reservoir heterogeneity, poor oil-water viscosity, well pattern and spacing, etc., the contradictions of small layers within strata gradually intensifies, and the effect of development becomes worse. Therefore, further subdivision and reorganization of developed strata is one of the main technical means to solve the contradiction between layers and enhance oil recovery. In order to solve problems that the evaluation technology of existing strata is fuzzy and unspecific and the timing of adjustment is difficult to grasp, the theory method of maximum membership degree in fuzzy mathematics is used in this paper. The inter-layer variation coefficients of boundary oil-bearing area coverage rate, boundary oil-bearing sand body superposition rate, oil-bearing rate, saturation, seepage resistance and other indicators are selected as the evaluation of strata. By evaluating and recognizing the present situation of strata from a quantitative and hierarchical perspective, the evaluation of the development status within strata and the timing of the adjustment within strata are quantitatively evaluated, which is very important guiding significance for understanding the current stage of the oilfield strata and further enhancing oil recovery through the adjustment within strata.