Plant responses to grazing form part of an adaptation strategy that enables them to survive and reproduce. Plant phenotypic responses are important to characterize grazing-induced plant mechanisms in grassland ecosystems. In the present study, we investigated how grazing and enclosures affect individual traits of Poa alpigena, the primary plant species in alpine meadows of the Qinghai-Tibet Plateau. The objectives of our research were to (1) reveal the different P. alpigena stem and leaf response traits affected by grazing and enclosures, and (2) determine the sensitivity of the phenotypic plasticity of different traits during grazing.The present study was conducted using field experiments involving various grazing and enclosure conditions on the Qinghai-Tibet Plateau. We compared the effects of annual grazing (YG), summer grazing (SG), winter grazing (WG), 3-year enclosure (UG3), 5-year enclosure (UG5), and 12-year enclosure (UG12) on P. alpigena functional traits. The experimental data for YG, SG, WG, UG3, UG5, and UG12 were randomly collected from sample areas in early August 2014. Plants with intact organs were collected from six plots (1.0 m × 1.0 m), with nine collections from each plot for a total of 54 plant samples. Plant height, number of leaves, leaf length, leaf width, stem diameter, stem length, root length, root thickness, ear length, and other phenotypic traits were determined. Averages for leaf length and width were calculated using these data. Leaf area was measured using a digital scanner and image analysis software, and the average individual leaf area was calculated. After phenotypic traits were assessed and recorded, the stems, leaves, spikes, and roots were separated and dried. The dry weight of the stems, leaves, spikes, and roots of each plant was determined.The results showed that under long-term grazing conditions, there was a significant decrease (P < 0.05) in root weight, number of leaves, plant height, number of branches, leaf length, leaf width, leaf area, stem diameter, stem length, root length, root thickness, spike length, total leaf quality, stem weight, spike weight, and whole-plant weight. Under short-term enclosure conditions, the recovery of functional properties such as leaf width, leaf quality, simple leaf quality, stem weight, spike weight, and root weight was not significant (P > 0.05). The results suggest that the recovery of P. alpigena traits on degraded grassland due to short-term grazing were associated with conservation. We also determined the spectrum of P. alpigena trait plasticity and observed that phenotypic variations in spike weight, stem weight, total plant weight, number of tillers, stem length, and plant height were high, indicating that these characteristics are sensitive to grazing. Phenotypic variations in leaf width, number of leaves, stem diameter, and root diameter were low, suggesting that these are inert characteristics. Generally, phenotypic changes are significant in the adaptive strategy used by P. alpigena to manage the effects of long-term grazing.