Abstract: In response to the increasing hub heights of large-scale wind turbines and the growing demand for wind energy development in low-wind-speed regions, this paper proposed a vertical lattice support structure to overcome the limitations of conventional steel tubular towers in structural efficiency, transportation, and dynamic performance. The proposed structure consisted of a tower piece, a transition piece, and a vertical lattice piece, thereby improving material utilization and facilitating modular construction. Based on this scheme, a complete key technology system was established for the proposed structure. An equivalent tower modeling method was developed to improve the efficiency of load simulation and design iteration for complex lattice structures. A multiscale integrated fatigue assessment method was proposed to achieve rapid transformation from the fatigue load Markov matrix to the hot-spot stress Markov matrix while maintaining both computational accuracy and efficiency. A cast-steel joint transition piece was developed and optimized through parametric analysis to ensure reliable load transfer from the nacelle to the lower lattice piece. In addition, a multi-parameter collaborative optimization framework was established to reveal the influence of key design parameters on structural steel consumption. The proposed support structure provides a new theoretical basis and technical reference for the engineering application of ultra-high wind turbine support structures.