Abstract: The three-dimensional broadband spatiotemporal ground motion field at the regional scale is a key factor for the aseismic design of engineering structures and urban earthquake prevention planning. This study introduces a revised three-dimensional broadband hybrid ground motion simulation method with the radiation pattern modification in the stochastic finite fault method to express the three-dimensional high-frequency (1 Hz-10 Hz) ground motions, combined with the low-frequency (0.1 Hz-1 Hz) three-dimensional ground motions from the spectral element method. The method proposed is applied to Xiong'an New Area to demonstrate its reliability and advantages. The study first selects the highly active Xushui-Dacheng Fault within the Xiong'an New Area as the seismic source and synthesizes the broadband ground motion spatiotemporal fields. The results are compared with those of the frequency-wave-number domain (FK) method and the NGA-West2 ground motion prediction equations to validate its reasonableness and highlights the advantages of simulating broadband ground motions. The three-dimensional peak ground acceleration, peak ground velocity, and response spectra at different periods in the Xiong'an New Area are presented. the near-field broadband ground motion from M_w6.3 earthquake on the Xushui-Dacheng Fault clearly demonstrates near-fault effects such as directivity and hanging wall effects. The PGA in southern Rongcheng, in northern Anxin, and in southwestern Xiong counties exceeded the regional seismic acceleration threshold, with seismic intensity in these areas surpassing the current fortification level of VIII. These findings serve as valuable reference data for seismic fortification efforts in the Xiong’an New Area.