Abstract: To address the co-design challenge of achieving both high lift-to-drag ratio and volumetric efficiency in hypersonic vehicles, this paper proposes a design methodology integrating osculating cone waverider parametric modeling, global sensitivity analysis, and multi-stage sequential optimization, aiming to break through the low volumetric efficiency limitation of traditional waveriders and develop a novel waverider-like configuration with superior aerodynamic and volumetric performance. A hierarchical model fusion generation mechanism is established. Initially, multi-objective optimization is conducted using the NSGA-II algorithm based on osculating cone theory, generating a Pareto front solution set covering inviscid lift-to-drag ratios of 5–20 and volumetric efficiencies of 0.05–0.13. A representative balanced solution’s windward surface is selected as the baseline for subsequent waverider-like configuration design. The leeward surface is parametrically designed by introducing a spine function to control axial length-height variations, combined with CST functions and curvature variation laws to regulate transverse width-height distributions. Then, global sensitivity analysis reveals the dominant influence of leading-edge compression angle and height allocation coefficient on aerodynamic performance, validating the critical role of windward surface preselection. Finally, a two-stage sequential optimization strategy is implemented: secondary optimization incorporating leeward surface design variables is performed on the reduced design domain (80% reduction from primary optimization), yielding an optimized configuration featuring a flattened forebody, axially curved mid-section, swollen aft-body, and airfoil-like cross-sectional profiles at lateral edges. Performance evaluations demonstrate that under design conditions (40 km altitude, Mach 19.7, optimal angle of attack of 6.5°), the optimized configuration with 2 mm fillet radius achieves a viscous lift-to-drag ratio of 3.04 at 0.15 volumetric efficiency. Under off-design conditions (Mach 10, optimal angle of attack of 10°), the viscous lift-to-drag ratio remains at 2.92 with merely 4% degradation, indicating robust wide-speed adaptability under high volumetric efficiency constraints. Comparative studies show 16% improvement in viscous lift-to-drag ratio over full-CST parameterized configurations at equivalent volumetric efficiency, and 7% enhancement in volumetric efficiency compared to osculating axisymmetric waveriders under identical aerodynamic constraints. These results verify that the proposed multi-stage optimization method achieves superior balance between aerodynamic efficiency and volumetric capacity, providing a paradigm for hypersonic vehicle multidisciplinary design.