Aims <p>Biomass allocation and nutrient content of plants reflect the trade-off of resource partition and adaptation strategy to a changing environment. Community-specific allocation strategies can clarify plant resource adaptive trade-offs and offer vital insights for guiding vegetation restoration and sustainable management.</p> Methods <p>The biomass partitioning and carbon (C), nitrogen (N), and phosphorus (P) content in leaf, stem, and root of plant were investigated in 119 grassland communities, which were categorized into three types (<i>i.e.</i>, farming-withdrawn grassland, FW; natural grassland, NG; underforest grassland, UG).</p> Results <p>There were significant scaling relationships between leaf and stem biomass (α ≈ 0.75), root and shoot biomass (α ≈1.35), both showing strong allometric relationships, with no significant differences among the three communities’ types. The P allocation followed allometric relationships in FW and NG communities, and the N allocation followed allometric relationships in UG community. The weak correlations between root:shoot biomass and root:shoot nutrient ratios in all communities, coupled with the weak leaf:stem biomass-nutrient relationships in both NG and UG communities, collectively demonstrated decoupling effects between biomass and nutrient allocation. Leaf area index (LAI) and community-weighted mean height (CWMH) are significantly correlated with biomass allocation; Soil organic carbon (SOC), precipitation, and soil bulk density were the most significant influences on biomass.</p> Conclusions <p>All three grassland community types exhibited similar allometric relationships in biomass allocation, while nutrient allocation patterns varied with community types. Plants optimize resource utilization strategies in different community types, and the decoupling effect between biomass and nutrient allocation enhances community stability and resource use efficiency.</p>