Abstract: The hollow roof spoiler, a key rear-exterior styling component of passenger vehicles, tends to generate broadband aeroacoustic noise when the vehicle travels at elevated speeds, thereby compromising the acoustic comfort of second-row occupants. To address this issue, the present study integrates the lattice-Boltzmann method (LBM) with statistical energy analysis (SEA), and performs a systematic characterization and optimisation of the broadband aeroacoustic noise radiated by the hollow roof spoiler. The analysis demonstrates that, in the 250-1000　 Hz frequency band, the dominant noise mechanisms involve vortex shedding from the supporting brackets, flow separation at the spoiler’s leading edge, and vortex shedding from the trailing edge, while in the 2000-4000 　Hz frequency band, the noise is principally contributed by the leading-edge region of the spoiler. By refining the leading-edge contour of the spoiler, reshaping the geometry of the support structure, and regulating the hollow area, the broadband noise level can be markedly reduced. Numerical simulations indicate that the optimized configuration reduces the deterioration in articulation index for the second-row passengers by 6.3 percentage points. Wind-tunnel tests conducted under representative operating conditions validate the effectiveness of the proposed design modifications. Consequently, this work provides practical design guidelines for the mitigation and optimization of broadband aeroacoustic noise produced by hollow roof spoilers in passenger-vehicle applications.