The restoration of Land Used for Qinghai-Tibet Highway Construction is an important part to restore degraded alpine grassland in the Qinghai-Tibet Plateau, China. C, N, P stoichiometry is considered an effective tool to disclose the synergistic adaptation of plant growth and element availability in the process of plant restoration on Land Used for Qinghai-Tibet Highway Construction. A field survey was carried out to investigate whether the Land Used for Qinghai-Tibet Highway Construction contributes to shifts in the C, N, and P stoichiometry of the leaves and soil of the plant community, and to identify the N- or P- limitation status of plants in the natural community and restorable communities growing for nearly two decades as part of the natural regeneration of Land Used for Qinghai-Tibet Highway Construction. Seven survey sites were selected along the Qinghai-Tibet Highway, in which four groups of restorable and natural plots were arranged. Then, four subplots for each plot were randomly used to harvest community leaves and soil samples. Organic C, N, and P concentrations of plant leaves and soil samples were analyzed by using the external heating method, the Kjeldahl acid-digestion method, and the Mo-Sb-Ascorbic acid colorimetric method, respectively. The independent-sample t test and paired t test were used to analyze differences in leaf C, N, and P stoichiometric variables and differences in soil organic C, N, and P stoichiometric variables from restorable and natural plots, respectively. The relationship between leaf and soil C, N, and P stoichiometric variables was analyzed by Pearson correlation. This study showed that the plant communities had gradually established on the Land Used for Qinghai-Tibet Highway Construction at each study site, but that the plant composition was different between restorable communities and natural communities after 18 years natural restoration. The leaf N concentration of restorable communities was higher than that of natural communities;thus, inducing lower leaf C : N, which showed that the N nutrient-use efficiency of the restorable communities was lower than that of the natural communities. A high percentage legume plant and relatively adequate available N supplement may be the major reasons for lower leaf C : N in restorable communities. The soil organic carbon (SOC) of the restorable plots at both 0-10 cm and 10-20 cm soil depths were significantly lower than those of natural plots, and the soil total nitrogen (STN)shared the similar pattern with SOC. The soil total P of the restorable plots in the 10-20 cm soil layer was higher than that in natural plots. These results indicate that the soil fertility of restorable communities did not reach the level of natural communities, but that it had improved significantly. Leaf N and STN had no significant correlation;however, leaf P was significantly positively correlated with soil total phosphorus (STP), showing that leaf P is influenced by STP to some certain extent. Using the thresholds of N, P-limitation, and the results of the correlation between leaf elements and soil nutrients, this study shows that plants are probably P-limited in the study region, with plants in the restorable communities suffering from more intense P-limited conditions than those in the natural communities.