Abstract: Blades have a range of structural performance and quality depending on the topology of composite fiber cloth and soft sandwich materials. To maximize the design potential of material space layout,this study proposes a macro topology optimization approach for blades by using phase variables. The mathematical formulation for topology optimization is established,with elemental pseudo density as design variable,minimum weight as the objective function and the strength as the constraint. The problem is solved using a combination of the modified full stress approach and the relational mapping inversion principle,with optimization performed using the Abaqus-Python-Matlab joint platform. Taking 1.5 MW blade as an example,the optimized space layout of blade composite and soft sandwich material is achieved,and the irregular area is adjusted using the equivalent design criteria. The results indicate that the optimized blade meets the requirements for strength,while dramatically reducing the mass,also verifying the effectiveness and feasibility of the proposed method.