Cadmium (Cd) is one of the widely distributed and polluted heavy metals. With serious toxicity, Cd not only affects the growth and development of plants, but also endangers human health. This review summarizes recent research advances and underlying mechanisms of physiological and biochemical responses to Cd stress in plants. We also review and discuss plant responses in photosynthetic systems, reactive oxygen species and reactive nitrogen species, antioxidant defense systems, hormones, calcium signals, and their underpinning proteomics and genomics mechanisms. We aim to form a theoretical basis for future research on understanding the physiological and biochemical mechanisms of plant responses to Cd stress.