In this study,changes of ABA content in leaves of four species of the mung bean（BL9,BL11,BL935,BL985） in seedling,blossom and maturation were determined by the ELISA method.The relationship between dynamic distribution of ABA and resistance to drought was analyzed.The results showed that ABA content of leaves of all mung bean varieties increased gradually from seedling,blossom to maturation.ABA content in mung bean leaves was lower in the drought-resistant varieties.The differences of ABA content in mung bean leaves at blossom were significant among varieties with different resistance to drought.