Plastic sex expression and allocation is common in angiosperm. Many plant species adjust their relative allocation to male and female organs in response to the environmental conditions in order to optimize sex functions in different environments. Large variation in anther-to-ovule ratios is presented among the natural populations of Ficus tikoua in the Southwest China. And it is associated with differing distributions of male flowers in the figs. Three male flower distributions occur, namely concentrated around ostiole (OS type), scattered throughout the fig cavity (SS type), and intermediate type (IS type). The anther-to-ovule ratios of OS type were significantly higher than those of SS type. We employed a maximum entropy model to simulate the potential suitable areas of F. tikoua based on 339 documented distribution sites. The key environmental factors contributing to the regional distribution of different plant phenotypes and restricting the expansion of the plant among regions were assessed. The distribution of the three phenotypes were largely allopatric, with OS type centered on Sichuan Basin, SS type concentrated on Hengduan Mountains-Yunnan Plateau, and co-occurrence on Guizhou Plateau. The environmental conditions associated with phenotype were different. OS type was associated with lower altitude, lower minimum temperature of the coldest month, and greater temperature seasonality. SS type was linked to higher altitude, stronger solar radiation, and smaller temperature seasonality. The different environmental conditions in each distribution region restricted cross-region expansion, brought about the variation of flower phenology of the plant and the population dynamics of its pollinating fig wasps, which might contribute to the divergence of sex allocation strategies of F. tikoua.