Abscisic acid (ABA), as a class of phytohormones containing a sesquiterpene structure, is involved in plant growth and development and regulates plant responses to environmental stresses. In order to investigate the effect of exogenous ABA immersion on seed germination and early seedling growth and development of alpine pasture Onobrychis viciifolia under drought conditions, the present study utilized different concentrations of ABA to pre-treat red bean grass by immersion, and 10% PEG to simulate drought stress, and to detect and analyze the physiological characteristics of seed germination and early seedling growth of O. viciifolia. The results of the study showed that seed imbibition using ABA (5 mg·L^-1) significantly increased the seed germination rate, germination potential, germination index, and seed vigor index of O. viciifolia under drought stress. Meanwhile, ABA(10 mg·L^-1) treatment significantly promoted the primary root elongation and root-crown ratio, and increased the antioxidant enzyme activities as well as the content of osmoregulatory substances of O. viciifolia seedlings, which effectively alleviated drought-induced oxidative damage. However, higher concentrations of ABA (>20 mg·L^-1) inhibited the germination and seedling growth of O. viciifolia. Therefore, it was concluded in this study that low concentrations of exogenous ABA (5 and 10 mg·L^-1) treatments were able to promote seed germination and reduce oxidative damage in seedlings under drought conditions, a finding that provides a theoretical basis for the popularization of high-quality forage grasses in arid regions.