The heterotrimeric GTPbinding protein (G protein) mediated signal transduction is a key component in the regulation of growth, development and stress response in eukaryotes. Recent studies have shown that heterotrimeric G proteins consist of three subunits: α, β and γ. The core components and the basic biochemical properties of G proteins are conserved in animals and plants. However, new regulatory mechanisms of G proteins in plants have been revealed. G proteins have been identified as essential regulators in many agronomic traits, including seed yield, organ size, biological and abiotic stress, nitrogen use efficiency and so on. Therefore, studies on G proteins have become a hot area in plant science. In this review, we summarized the basic composition and the structure of G proteins, the acting mode of G proteins in animal and plants, and the function of G proteins in the regulation of plant growth, development, and stress response including drought, temperature and salt, with an aim to offer a reference for related research and provide a theoretical basis for crop breeding by using G proteins.