The invention provides a determining method for conglomerate oil reservoir chemical flooding well spacing. The method comprises the steps of (1), solving formation pressure gradients among injection and production wells according to injection and production well spacing and injection and production well pressure differences; (2), obtaining injection well permeability-formation pressure gradient relational expressions through logarithm regression; (3), dividing the injection and production well pressure differences into different intervals, and obtaining corresponding formation pressure gradient-injection and production well spacing relational expressions through exponential regression according to the injection well permeability in the intervals and the formation pressure gradients among the injection and production wells obtained in the step (1); (4), drawing a plate; and (5), obtaining the corresponding formation pressure gradients on the plate obtained in the step (4) through an injection well permeability-formation pressure gradient curve, and obtaining the injection and production well spacing under the formation pressure gradients according to a formation pressure gradient-injection and production well curve in the corresponding injection and production well pressure differences. According to the method provided by the invention, the conglomerate oil reservoir polymer flooding well pattern well spacing can be obtained rapidly and accurately.