<p>China is among the countries most severely affected by global climate change, facing two predominant climatic challenges: droughts and floods. These hazards pose direct and significant threats to agricultural production. To provide a comprehensive understanding of this issue, we conducted a systematic review of 154 peer-reviewed studies published between 2004 and 2024, following the PRISMA 2020 guidelines. The review focuses on the spatiotemporal distribution of droughts and floods, mechanisms of drought–flood alternation, agricultural impacts, and adaptation strategies across China. Results reveal that droughts are primarily concentrated in North, Northwest, and Northeast China, while floods frequently occur in the Yangtze, Pearl, and Huai River basins. The increasing prevalence of drought–flood alternation has intensified challenges in agricultural planning and water management. Crop vulnerabilities vary by region and season, reflecting different sensitivities to water stress. Key adaptation measures include the development of disaster-resilient crop varieties, the implementation of modern irrigation technologies, agricultural structural adjustments, and the establishment of integrated early warning and insurance systems. The review also outlines future research priorities, such as improving high-resolution climate forecasting, optimizing regional water governance, enhancing cross-sectoral data sharing, and advancing ecological restoration. This synthesis provides a critical evidence base to support resilient agricultural development under a changing climate.</p>