In order to explore the changes of starch content and physical chemistry properties of mung bean during cooking, optimize the cooking time of mung bean, and provide theoretical basis for mung bean cooking processing. Taking mung bean as the main raw material, the starch content and starch properties were determined and analyzed by traditional cooking method and sampling at 10 min interval. The results showed that the total starch content and amylose/amylopectin content in mung bean decreased with the extension of cooking time; the solubility increased after 30 min of cooking, and the solubility reached the maximum at 60 min; the swelling power decreased and tended to be stable after 50 min; the paste transparency increased significantly after 40 min of cooking and reached the maximum at 60 min; the coagulation stability increased gradually after 40 min. The results of correlation analysis showed that cooking time was significantly positively correlated with solubility, negatively correlated with total starch content and swelling power, positively correlated with transmittance, and negatively correlated with amylose and amylopectin content and coagulation volume. The cooking time is the main factor affecting starch content and properties of mung bean, and starch content directly affects the swelling power, transparency and other physical and chemical properties of mung bean. In the process of mung bean food processing, different cooking time can be selected according to the processing purpose.