Fish reproduction often depends on specific hydrological processes that serve as environmen-tal triggers and dams,by altering flow regimes,profoundly affect the hydrological conditions essential for fish reproduction.However,in the absence of continuous long-term fish monitoring data,the hydrological conditions and dynamics on which fish reproduction depends remain poorly understood.In this study,the reach of Jinsha River downstream of Xiangjiaba dam(construction began in 2006,operation in 2012)was selected for investigation,and we systematically analyzed the hydrological characteristics and dynamics of potential spawning windows in the dammed river from multiple perspectives:the hydrological back-ground,extreme events,event types,and intra-annual to interannual variability.Based on daily flow data from 1980 to 2020,a method was developed to identify the hydrological characteristics of potential fish spawning windows based on water-level rising hydrological events.Results show:(1)The long-term trend in mean annual flow in the study reach was not significant,but the interannual coefficient of varia-tion(CV)presented a significant downward trend since dam construction,indicating a notable reduction in flow regime variability.(2)The frequency and magnitude of extreme flood events exhibited an overall declining trend,with a gradual reduction in high-peak flood events.(3)The hydrological events identified based on rising processes could be categorized into eight typical types,with events indicative of potential spawning activity being mainly concentrated within specific periods of the year(early March to late Sep-tember),forming a relatively stable seasonal window.(4)After the dam was constructed,no significant abrupt change was observed in the annual number of hydrological events suitable for fish reproduction,however,systematic adjustments occurred in event magnitude,duration,and type structure,characterized by a decline in relative peak magnitude,a shortening of rising duration,and a reduction in event type di-versity.The findings of this study suggest that the evolution of hydrological processes associated with po-tential fish spawning windows in dammed rivers is primarily manifested as a reshaping of event type structure rather than a mere change in water volume.This study will provide a theoretical basis for habitat protection and restoration of fish species in dammed rivers,as well as for decision-making to improve eco-logical operation.