Compared with conventional vehicles, waverider is expected to overcome the limitations of lift-to-drag ratio in hypersonic conditions and considered one of the most promising configurations for hypersonic vehicles. Typically, waverider exhibits good aerodynamic performance under the design condition. However, maintaining such performance under off-design condition is challenging, leading to insufficient aerodynamic performance across a wide range of speed. This paper first proposes a novel design method for double swept waverider, where lift exhibits nonlinear growth with an increasing angle of attack and generates strong surface vortex lift at low speeds. These characteristics effectively accommodate both high-speed and low-speed conditions, improving waverider performance under off-design condition across a wide range of speed. The curved-cone-derived waverider design based on the projection approach enables simultaneous control of the basic flow field and planform contour, addressing the limited design space issue of conventional methods while enhancing aerodynamic performance under the design condition. Furthermore, to achieve optimal wide-speed-range performance, an aerodynamic estimation method is developed and combined with an improved multi-objective cuckoo search algorithm for optimization. Subsequently, the numerical method is applied to the optimized representative configurations under the hypersonic condition and the expected aerodynamic performance is obtained. The subsonic aerodynamic performance of waverider is also investigated. The double swept waverider in this research generates strong vortex lift and ideal longitudinal static stability performance at subsonic speed, which optimizes the wide-speed-range aerodynamic performance.