Plant community productivity is an important parameter that reflects the production capacity of plant communities under the natural conditions. Exploring the spatial distribution pattern and driving factors of plant community productivity is not only conducive to further understanding plant community productivity and its response to climate change, but also is of great significance for maintaining the stability and sustainable development of terrestrial ecosystems. This study carried out a field survey of plant communities along the hydrothermal gradient of the West-East Transect of China (WETC). We used survey data to calculate the plant community aboveground biomass (AGB) and aboveground net primary productivity (ANPP). Combined with environmental factors such as mean annual precipitation (MAP), mean temperature of the growing season (T_gs), CO₂ partial pressure (Pco₂), and the distribution pattern, as well as the driving factors of plant community productivity are discussed. The west-east 4000 km transect of China was set along the latitude 30°N, with a span of approximately 5° and a wide geographical distribution range. The WETC had an apparent precipitation gradient and a large temperature span. It also had good transition characteristics of vegetation, climate, and other environmental factors. At the same time, owing to the influence of the Qinghai-Tibet Plateau, the WETC formed a significant CO₂ partial pressure gradient. In summary, the unique environmental advantages and hydrothermal gradient of WETC provide a new platform for studying plant community productivity. AGB and ANPP of plant communities had evident longitudinal and vertical zonal distribution characteristics in WETC, that is, with an increase in longitude, the ANPP and AGB of the plant community showed a logistic growth trend, while ANPP and AGB showed a linear decreasing trend with increasing altitude. The environmental factors could well explain their spatial distribution. Firstly, ANPP, AGB, MAP, T_gs, and Pco₂ were significantly positively correlated with WETC; that is, ANPP and AGB showed a logistic growth trend with the increase in MAP and Pco₂. AGB and ANPP increased linearly with increasing T_gs. Secondly, ANPP and AGB had significantly negative correlations with solar radiation (SRAD), wind speed (WS), and pH. ANPP and AGB showed a linear decreasing trend with the increase in SRAD and soil pH, and an exponential downward trend with the increase in WS. In the West-East Transect of China, in addition to MAP and T_gs, Pco₂ also had an increasing effect on the distribution pattern of ANPP and AGB due to the impact of the particular environment of the Qinghai-Tibet Plateau. Our findings provide new insights into the response mechanisms of community productivity in high-altitude areas. Overall, the WETC had good transect potential and it may form a new transect system with the incorporation of the WETC, Northeast China Transect (NECT), and North-South Transect of Eastern China (NSTEC), to provide an improved platform for exploring the relationship between terrestrial ecosystems and global change in China.