The invention provides a three-stage subdivision method for retarding the interlayer interference of a fault-block oil reservoir with an ultrahigh water-cut stage and multiple oil layers. The method comprises the steps: (1) analyzing layer series recombination influencing factors, namely area, reserve, strip width, physical properties, energy and residual oil saturation, of each longitudinal small layer one by one, so as to obtain a comprehensive evaluation result for small layers; (2) under the guidance of technical policy limits for layer series recombination, dividing small layers into reservoir layers I and reservoir layers II, and respectively forming a development layer series by small layers I and small layers II which have similar seepage characteristics; (3) for situations that local area still does not meet the technical policy limits, adopting separate production and separate injection; (4) carrying out variable-density perforating on new drilled wells according to the differences of the residual oil enrichment states and physical properties of reservoir layers. According to the method, the longitudinal interlayer interference is retarded to the maximum, and the method is clear in thinking and simple and convenient in application, so that a technical support is provided for the further increase of the recovery ratio of the fault-block oil reservoir with the ultrahigh water-cut stage and the multiple oil layers.