Humulus scandens (Lour.) Merr. is a type of dioecious climbing herb. Many studies have shown that the availability of external supports has an important influence on the morphological and physiological activities, biomass allocation, and reproductive strategies of climbing plants. Because of the gender ramet expression of dioecious plants, only the female and male plants that received support were able to grow to a position of higher illumination; thus, these populations were able to successfully achieve pollination and seed dispersal and out-compete other plant communities. In their natural state, in which branches are subjected to varying levels of illumination, the support available has an influence on the distribution, distance, shape, size, strength and texture of dioecious climbing herbs; different branches of female and male plants often look different depending on the support available. There is a paucity of research on the effect of light heterogeneity on plant morphology, physiology, biomass, and reproduction at the branch level. Therefore, we conducted this study to investigate the influence of external support on the photosynthetic characteristics and biomass structure of H. scandens. We also investigated the gender differences regarding the use of external supports and ecological adaptations in response to external support. H. scandens was grown under three artificial scenarios: tree support (height (3±0.5) m), shrub support (height (1±0.5) m), and no support. The following characteristics were measured for each plant: leaf area, photosynthetic parameters, chlorophyll, and soluble sugar. We also measured the ratio across the stem, leaf, and flower at branch, component, and plant levels, respectively. Significant differences were observed across genders in response to external support in multiple biological parameters, including single leaf area, total leaf area, leaf area ratio, and specific leaf area. Leaf areas of female branches were greater than those of male branches. Significant differences were also observed across the three variations of external support for the amount of chlorophyll a; however, no difference was observed for the amount of chlorophyll b and chlorophyll a/b. External support also had a significant impact on all four photosynthetic parameters of branch leaves (P <0.05). The strongest effect was observed for stomatal conductance, and the least impact was observed on intercellular CO₂ concentration. A significant association was found between external support and the amount of soluble sugar (P <0.01). In addition, soluble sugar in male plants was significantly higher than that in female plants (P <0.01). 3) At the branch level, a significant association was observed between the external support and ratio of leaves and stems in male branches (P <0.05). However, no association was observed between the external support and ratios of leaves, stems, and flowers in female branches (P>0.05). The ratio of the vegetative component in male branches and ratio of the reproductive component in female branches was significant at the component level. External support significantly affected the ratio of leaves (P <0.05) at the individual plant level. We also observed significant differences in the ratios of stems and flowers between genders and across support type. The photosynthetic characteristics and biomass structure of both female and male H. scandens showed a strong response to the heterogeneous external support, which greatly improved physiological integration and adaptability of single H. scandens. Therefore, results from this study are valuable for additional investigation of the ecological adaptability of dioecious climbing plants.