Climate warming has become a credible fact, owing to the increase of greenhouse gases. It is generally believed that ecosystem responses to elevated temperature are highly sensitive and rapid in high-latitude and high-elevation regions, especially in the Qinghai-Tibetan Plateau (QTP). The QTP has been considered as an ideal region for studying responses of terrestrial ecosystems to global climate changes. Representing a typical QTP vegetation type, alpine meadows are extremely fragile and highly sensitive to climate warming. Once they are destroyed, it is very difficult for these meadows to recover quickly, which results in their degradation or desertification. Therefore, it is extremely important and urgent to investigate the relationship between vegetation characteristics and environmental factors under climate warming in the QTP. We used infrared heaters to control experimental warming. Fifteen experimental warming plots (EWPs) of 2 m × 2 m area and 60 non-experimental plots (NEPs) of 20 cm × 20 cm or 30 cm × 30 cm areas were established in an alpine meadow. EWPs included three treatments: 0 W/m² (control, T0), 130 W/m² (increasing ground temperature by about 1°C, T1), and 150 W/m² (increase of about 3°C, T2). Each type of treatment had five replications. Vegetation height, coverage, above- and belowground biomass were measured in NEPs. In EWPs, vegetation height, coverage, species richness, plus temperature and moisture were investigated after 1 year of warming. Then, detrended correspondence analysis (DCA), redundancy analysis (RDA), stepwise regression analysis, and path analysis were used to find correlations among vegetation characteristics, temperature and moisture. Our results show that log-transformed species richness was significantly linearly correlated with the reciprocal of absolute temperature in the alpine meadow. Air temperature at 20 cm height, ground temperature, and soil temperature in the 0-20 cm layer had greater impacts on species diversity (R²>0.6, P<0.01) than deep soil temperature in the 40-100 cm layer (R²<0.5, P<0.05). Average activation energy of metabolism in alpine meadow vegetation (0.998-1.85 eV) was greater than that of the metabolic theory of biodiversity (0.6-0.7 eV). This indicates that the activation energy of alpine meadow vegetation was high, enabling it to survive such harsh conditions as low temperature, drought, and gales. In DCA ordination, the relationship between vegetation characteristics and environmental factors fit the linear model best. Therefore, RDA ordination was chosen to study correlation among vegetation characteristics, temperature, and moisture. In RDA ordination, temperatures had a greater impact on aboveground vegetation, whereas soil moisture had more influence on above-and belowground vegetation. In a certain range, both elevated temperature and increased soil moisture enhanced vegetation growth most significantly in the meadow. In the stepwise regression and path analyses, soil moisture at 40 cm and 60 cm depths affected aboveground vegetation directly, whereas atmospheric relative humidity at 20 cm height and soil temperature at 40 cm depth affected it indirectly. Belowground vegetation was directly affected by soil temperature at 40 cm and soil moisture at 60 cm, and it was indirectly affected by soil surface temperature. It was also found that deep soil temperature and moisture influenced the growth of alpine meadow vegetation to a degree. We believe that this may be related to the melting of frozen soil caused by warming.