Many previous studies have demonstrated that understanding the functional traits of organisms (plants, animals, and microorganisms) can help clarify mechanisms of biodiversity changes in nature and accurately predict the impact of plant species on ecosystem functions and services from the individual to community levels. However, owing to the limitations of the traditional definitions of functional traits, most studies have focused on organ or species levels. Studies on functional traits at the community, ecosystem, regional, and global scales have used the simple arithmetical averaging method to scale up from species to community levels. The structure and composition of plant species are highly complex in natural communities, particularly forests. Significant differences exist in the relative contributions of different plant species among different regions. Therefore, using traditional methods involving simple arithmetic means in large-scale studies on functional traits is challenging. Accordingly, researchers have developed a new concept of plant community traits, systematically introduced the theoretical basis, and presented a normative derivation method of specific plant community traits to expand these functional traits into complex natural communities. In this study, plant community traits are defined as the functional or quantitative characteristics of plants at the community level and are expressed as the intensity (or density) normalized per unit land area. Furthermore, plant community traits may be further developed as two-dimensional characteristics considering the definition of “density” or “intensity.” For traits related to productivity or adaptation, the density and intensity of functional traits per unit land area should be considered as intrinsic efficiency (Traiteffi) and quantity traits (Traitquan), respectively, which are more ecologically significant and practical at community, regional, and global scales. Traiteffi can be calculated using simple arithmetic, geometric, and community-weighted means, considering data availability in natural communities, although they may not be accurate to some extent. Traitquan requires comprehensive or matched information on species composition and the relative contribution of each species to the natural communities. Based on this, we introduced the spatial variability of the two-dimensional characteristics of plant community traits and their influencing factors on a regional scale. These included the spatial variations of nitrogen and phosphorus content and storage and their influencing factors in plant communities on the Qinghai–Tibet Plateau, and sulfur content and storage and its influencing factors in typical plant communities in China. These new parameters of plant community traits may enhance the integration of different studies in the future, owing to a relatively unified land area, by incorporating functional traits, remote sensing, modeling, or flux.