Global warming caused by massive greenhouse gas emissions is one of the most concerned environmental problems, which will directly affect the growth and development of plants, and then affect the community composition and even the structure ecosystem. Water use efficiency, as an important indicator of plant foliar regulation of water physiological process in virtue of photosynthesis, is the key to the relationship between carbon and water cycle of ecosystem, reflecting the adaptation strategies of vegetation ecosystem to the rapid adjustment of environment and the change of resources, and also is the focus of current global change research. Foliar δ¹³C can be used as a key indicator to reflect long-term water use efficiency of plant, but the effect of global warming on foliar δ¹³C value is still controversial. Due to the obvious limitations of previous point-scale studies, the global meta-analysis was used to integrate 371 groups of data from 51 literature worldwide to evaluate the effects of the simulated warming treatment on the foliar δ¹³C value systematically in this study. The results showed that the simulated warming treatment could significantly increase the foliar δ¹³C by 0.6% (P < 0.001) comparing with the conventional treatment group, and the effect sizes of foliar respiration rate (R_d), stomatal conductivity (G_s), net photosynthesis rate (P_n) and carbon (C) were 0.237, 0.062, -0.140, and -0.019 (P < 0.05), respectively. The simulated warming treatment enhanced photosynthesis and increased foliar respiration rate (R_d), which led to the continuous consumption of photosynthetic products and the decrease of foliar carbon (C), and finally the decrease of foliar P_n and the enrichment of δ¹³C. Through further analysis of the affecting factors, it was found that the response of foliar δ¹³C to the simulated warming treatment was mainly controlled by warming duration, elevation and average annual temperature (relative importance index was 1.00, 0.97 and 0.92, respectively). In addition, different warming patterns had significantly different effects on the foliar δ¹³C. The infrared radiators, heating wires and soil-core relocation treatment had positive effects on the foliar δ¹³C (effect sizes were 0.70, 0.44 and 0.35, respectively), but the shading screens and open-top chamber treatment had negative effects on it (effect sizes were -0.17 and -0.09, respectively). The conclusion of this study has important theoretical significance for further understanding the response characteristics of plant water use under the background of global change, in order to provide theoretical basis and effective support for future research of plant growth in this field.