Due to the increasing length of wind turbine blades, reducing their weight has become the greatest challenge in blade design. Research indicates that only by arranging all possible fibers along the axial direction can the load-bearing capacity of a blade with the same material consumption be maximized; another way to reduce the weight of the blade is to decrease the excess stiffness of flutter. Specifically, the root section (which occupies 1/10 of the blade length but 1/3 of the blade weight) is cut into trapezoidal blocks equal in number to the connecting bolts. The trapezoidal blocks that contribute more to the flutter stiffness are prefabricated with unidirectional fabric and are called UD rods; those that contribute more to the torsional stiffness, except for the section at the root where T-nuts are placed, are processed with lightweight foam. After laying down the lower skin fabric, the trapezoidal blocks are arranged one after another, each wrapped with just one layer of fiber cloth, followed by laying the upper beam's unidirectional fabric and the foam board of the skin, then applying the upper skin fiber, and finally injecting the glue for molding in one go. Technical Indicators: The root connection is perfect, integrating all the advantages of the current two most effective methods of connecting T-bolts with metal sleeves and pre-embedding them, eliminating all their disadvantages, resulting in a higher connection strength; the reduction in trapezoidal block width makes it possible to replace the three-axis fabric laid around the root with unidirectional fabric, increasing axial stiffness by 55%; each trapezoidal block's cross-sectional height, length, and material can be independently variable, greatly increasing design freedom. By reducing only 40% of the unnecessary torsional stiffness, it is possible to reduce the weight of current large blades by 15% compared to the same period, and the overall cost by 10%. Market Prospect: There are already 86 countries around the world that have installed wind turbines, and China alone needs more than 15 billion yuan worth of blades each year. This invention (Chinese Invention Patent Authorization No.: ZL200910197175.5) can generate excellent economic and social benefits.