The ecosystem of ecologically vulnerable regions is changed by the interaction of human activities and natural environmental changes. The desertification, salinization, soil erosion and vegetation productivity decline are important problems faced by the ecologically vulnerable regions. As a critical issue of interdisciplinary research, ecological stoichiometry emphasizes to reveal the biogeochemical cycle of elements and the regulation mechanism of ecosystem on environmental change from the perspective of energy and element balance of ecosystem. It is of great ecological significance to carry out the research on ecological stoichiometry of carbon (C), nitrogen (N) and phosphorus (P) elements in the ecosystem:(1) to judge the limitation of N and P on plants to reveal the mechanism of nutrient regulation and biogeochemical cycle in terrestrial ecosystem; (2) to promote the in-depth understanding of biological adaptability to the environment; (3) to reveal the mechanism of carbon cycle and response of ecosystem to environmental change. To understand the C, N and P ecological stoichiometry in typically and ecologically vulnerable regions (agro-pastoral ecotone, forest-grassland ecotone, desert-oasis ecotone, the Loess Plateau vulnerable areas, the Qinghai-Tibet Plateau vulnerable areas and southwest karst areas) of China, we mainly summarized the recently researches of C, N, and P ecological stoichiometry in plants, litters, soils and soil microbes, as well as their responses to environmental changes. Then, we proposed the possible direction in the further research. The aim is to promote the development of ecological stoichiometry and ecological protection and restoration in typically and ecologically vulnerable regions. The results show that the C, N, and P ecological stoichiometry of plants, litters, soils, and soil microbes present strong correlations, and is significantly affected by soil, climate and biological factors, and human activities. In the ecologically vulnerable regions, the deserts and desertification areas in north China with higher N:P ratio are more likely to be limited by P, while the ecologically vulnerable regions, such as the Qinghai-Tibet Plateau vulnerable areas, southwest karst areas, and the Loess Plateau vulnerable areas are more likely to be limited by N. With the vegetation restoration, the nutrient limitation gradually changes from N limitation to P limitation. The relatively low nutrient concentration and C:N:P ratio in the ecologically vulnerable regions may explain the reason for lower productivity of vegetation, while the plants with higher N and P stoichiometric homoeostasis have stronger competitiveness and higher stability in poor environment. Future research should focus not only on the ecological stoichiometry of plant-litter-soil-microbe system in different scales and ecosystems, but also on the controlled field experiments involving long-term and multi factors interaction.