Is today's ancient building a traditional cultural building in China?

Not necessarily. Ancient architecture is the embodiment of local culture at that time, and the architectural style also varies from time to time. At present, there are many ways to copy the China cultural buildings you mentioned in Xuzhou, but in Nanjing, because of the Ming Dynasty, many retro buildings are copied according to the architectural style of Huizhou (Zhu Yuanzhang, an Anhui native of the Ming Dynasty), and many of them are copied from the buildings of the Republic of China, while in Beijing, the styles are different, so they are copied according to the quadrangle style of the Forbidden City, so cities.