In order to investigate the effects of low temperature stress during the initial flowering stage and prespraying with uniconazole（S3307） on leaf AsA-GSH cycle and yield of mung bean（Vigna radiata）, Lvfeng 5（L₅）and Lvfeng 2（L₂） were used as materials in this pot experiment. S3307 was pre-sprayed and treated with continuous low temperature（average 12 ℃） for 5 d and samples were taken every day to analyze the accumulation of reactive oxygen species（ROS）, changes in substance content of AsA-GSH cycle, content of osmotic adjustment substances in mung bean leaves and yield. The results showed that the accumulation content of hydrogen peroxide（H₂O₂） and malondialdehyde（MDA） in mung bean leaves were significantly increased by chilling damage at the initial flowering stage, and the content of ascorbic acid and glutathione were significantly increased. The yield per plant of L₅ was significantly decreased 14.87%-48.14%, and the yield of L₂ was significantly decreased 20.60%-56.18%. S3307 has the effect of resisting low temperature stress at the initial flowering stage. Under low temperature conditions, prespraying S3307 can effectively increase the soluble sugar content of mung bean leaves, significantly reduce the H₂O₂ and MDA content, and significantly increase the contents of AsA, DHA and GSH, GSSG. Spraying S3307 has the regulatory effect of increasing the yield of mung bean. Under normal temperature conditions, L₅ and L₂ in a single plant significantly increased by 4.70% and 7.87%, respectively. Under low temperature conditions, when treated at low temperature for 1-5 d, the yield of single plant increased 5.11%-12.54%, and the yield per plant was significantly increased 6.30%-32.91%. In conclusion, low temperature during the initial flowering period affected the physiological functions of mung bean leaves such as reactive oxygen species accumulation, AsA-GSH cycle and osmoregulation. Pre-spraying S3307 could effectively alleviate the effects of low temperature stress on mung bean physiology and yield, and this conclusion provides theoretical basis and effective measures for the production of mung bean resistance to low temperature production.