Macroecology is a subdiscipline of ecology and biology that intends to explain large-scale patterns of abundance, distributions and diversity of organisms using quantitatively statistical methods. The environment and evolutionary mechanisms underlying large-scale patterns of species richness is a fundamental yet controversial question of biology since the time of Wallace and Darwin, and has been the cornerstone of macroecology. With a rich flora, broad environmental/geological gradients, China provides a “natural lab” for testing the mechanisms of species richness patterns. Here, we compiled the distribution maps of 11,405 woody species in China, and, in combination with the current phylogeny of angiosperms, we 1) demonstrated the large-scale patterns of woody species richness and compositional turnover cross China, 2) evaluated the effects of contemporary climate, particularly environmental energy, water–energy dynamics and winter coldness, and 3) explored how long-term evolution influences current species richness patterns by detecting the phylogenetic structures in local floras. We found that species richness decreases from southern China to northern China and the Tibetan Plateau, and species composition changes the fastest in southeastern Tibetan Plateau. Species become younger and more derived towards the north. Winter temperature is the best predictor of species richness and species age. These results suggest that the patterns of woody species richness are mainly resulted from the increasing intensity of winter coldness from the equator to the poles, and hence support the freezing tolerance hypothesis.