The blade cross-section design of the helicopter rotor is the basis for studying the rotor dynamics design. A two-stage optimization design method combining joint topology optimization and shape optimization is proposed, which can be used for the design of blade cross-section. The first-level optimization uses SIMP as the material interpolation method for topology optimization. The blade volume minimization is the design goal, the displacement and stress of the blade joint are constrained, and the topology optimization model of the blade is established. The second-level optimization uses the reconstructed blade model to optimize the shape, reduce local stress concentrations, and find reasonable boundary node locations. The finite element analysis of the optimized model shows that the topology optimization and shape optimization can achieve the structural layout that meets the requirements of strength and stability, and provide a guiding plan for the structural design and optimization of the blade.