Strain uniformity is an important index to evaluate the performance of large disk forgings in aerospace. Taking turbine disc as the research object, this paper explores the reasons for the formation of low strain zone of turbine disc forgings, and proposes a topological optimization design method suitable for large disc forgings based on the addition and removal rule of "number of subunits - volume - number of subunits". The method adopts the allocation of appropriate volume for each column element, and adapts the relative height of each region by stacking and adjusting modules. Obtain the shape of the preforging with low complexity of the target shape. In order to verify the effectiveness of the optimization method, the paper takes deformation uniformity as the goal to automatically optimize the shape of large turbine disc preforging. After optimization, the deformation uniformity of the forging is increased by 45%, and there is no strain dead zone. The results of numerical simulation and production test show the reliability of the method proposed in this paper.