Abstract: In the context of increasingly frequent extreme weather events worldwide, waterlogging induced by flooding has emerged as a critical meteorological constraint on peanut production. According to precipitation characteristics during the growing season in the major peanut-producing areas of Henan, a field pot-culture experiment with waterlogging durations of 0, 3, 5, 7 d and 9 d (0 d serving as the control) is started on 29 August 2023, at Zhengzhou National Agrometeorological Experiment Station. Dynamic responses of photosynthetic and fluorescence parameters in peanuts under different waterlogging durations are systematically examined, and recovery experiments are subsequently conducted to explore the underlying physiological adaptation mechanisms and damage processes. Experimental results indicate that a moderate water increase during the early stage of waterlogging (3 d) temporarily enhanced photosynthetic performance. However, as the waterlogging period extended, sustained soil saturation inevitably led to root zone hypoxia, which significantly suppresses plant growth and progressively compromised photosynthetic function. Recovery experiments demonstrates that when waterlogging exceeded 7 days, photosynthetic function could only be restored to approximately 68% of the control level, indicating that complete recovery became difficult to achieve. Fluorescence imaging monitoring showes that, as waterlogging prolonged, the actual quantum efficiency of photosystem Ⅱ in leaves progressively decreases in a distinct spatial pattern from the leaf margin toward the base, with visible wilting symptoms appearing on the 7th and 9th day of treatment. Yield analysis indicates that short-term waterlogging of 3 d exerted a certain stimulatory effect on 100-pod weight and pod weight per plant. However, when waterlogging duration reached 5 d or longer, all measured yield parameters shift toward negative responses. Kernel weight per 100 seeds and full pod weight per plant begin to decline continuously from the very onset of waterlogging, with daily reduction rates reaching 1.65 g·d^-1 and 5.73 g·d^-1, respectively. It demonstrates that prolonged waterlogging persistently inhibits kernel development and the formation of high-quality pods. In summary, peanut response to waterlogging stress exhibits a distinct threshold effect: Short-term exposure (no more than 3 d) may induce compensatory growth via physiological adjustments, whereas prolonged stress (greater than 5 d) results in cumulative damage to the photosynthetic apparatus and yield formation processes, with such damage becoming largely irreversible beyond 7 d of waterlogging.