Recently, climate governance has entered a new phase of accelerating decarbonization. In order to achieve low-carbon buildings, natural ventilation has been widely used as it requires no fan power. However, there are great challenges for achieving effective natural ventilation in large-space public buildings especially in areas characterized by hot-summer and cold-winter climatic regions, due to empirically unsuitable ambient temperatures and theoretically complex joint effect of wind pressure and thermal buoyancy. Therefore, this numerical study was conducted on the performance of a natural ventilation strategy in a large-space public building in a hot-summer and cold-winter region by using computational fluid dynamics (CFD) methods. Simulations were performed by applying FLUENT software for obtaining airflow distributions within and around a typical low-carbon public building. The temperature distribution in the atrium of the building was simulated particularly for analyzing the natural ventilation performance in a large-space area. Results demonstrated that thermal pressure was dominant for the large-space building in the case study. The average indoor airflow velocities on different floors ranged from 0.43 m/s to 0.47 m/s on the windward side which met indoor ventilation requirements. Most areas of wind velocities could meet ventilation requirements. The natural ventilation performance could be improved by increasing the relative height difference between the air inlets and air outlets. These findings could help provide references and solutions for realizing natural ventilation in low-carbon large-space public buildings in hot-summer and cold-winter regions.