The Chinese genus Firmiana accounts for a large proportion of Firmiana in the world, and all other species except Firmiana simplex are endemic to China and have a narrow distribution range, with a high risk of extinction. It is of great significance to study the impact of climate change on Firmiana species distributed in China for the maintenance of biodiversity. Combining the distribution data of eight Firmiana species and CMIP6 climate data in multi periods, the Maxent model optimized by kuenm was used for potential suitable areas simulation in multi scales. The suitable scale for simulating potential suitable areas of the eight Firmiana species, area changes and migration direction of potential suitable areas, key conservation areas for Firmiana diversity and conservation gaps were studied. The results show that:(1) the suitable simulation scale for Firmiana is Asia; (2) The accuracy of Maxent model exceeds 0.9, indicating that the prediction results of the model are highly accurate; (3) Except for Firmiana major, most of the potential suitable areas of Firmiana species will expend in the future under climate change; (4) Migration direction of potential suitable areas of Firmiana species are mainly east and west, seldom large change in north and west, while latitudes don't change much; (5) The stably potentially suitable areas of Firmiana danxiaensis is smallest; (6) The key areas for Firmiana variation conservation are in Guangxi zhuang autonomous region, Yunnan, Guangdong, Hainan and other provinces and regions; (7) Conservation gap of Firmiana variation mainly distributed in middle Guangxi zhuang autonomous region and northern Hainan province; (8) Critical areas for the conservation of Firmiana diversity are eroded by man-made surfaces. The study analyzed the impact of climate change on the eight Firmiana species distributed in China, the changes of their potential habitat, and the conservation status of Firmiana diversity in China. It can provide relevant suggestions for the establishment of diversity conservation corridors for Firmiana in China, and provide references for the development of diversity conservation plans and corresponding measures.