<p>In the realm of wind energy conversion systems, the aerodynamic loads exerted upon the blades of VAWTs exhibit significant disparities when juxtaposed with those of HAWTs. The VAWT blades undergo periodic variations in angle of attack, which precipitate an uneven distribution of aerodynamic loads and, consequently, induce substantial stress fluctuations. To ameliorate this phenomenon, the design of an innovative web structure for VAWT blades, divergent from the HAWT blade design, has been proposed to mitigate stress fluctuations. Employing a topology optimization methodology, the spatial configuration of the VAWT blade’s web structure has been meticulously optimized. This optimization process integrates the considerations of discrete global load design and local reinforcement design, culminating in the development of an X-web structure that deviates from the traditional double web structure. Empirical verification has substantiated that the refined X-web structure achieves a reduction in stress fluctuation variance by 50 % relative to the conventional double-web structure.</p>