Designing flood standard is crucial in the planning, design, and operational management of water resources and hydropower engineering. The determination of the standard is influenced by various factors such as the socio-economic conditions, the population size, and the scale and efficiency of engineering construction. With the intensification of climate change and the advancement of new theories and technologies, the international community began to explore new flood standard selection criteria and climate change adaptation policies to meet the requirements of flood management. Some typical developed countries such as the United States, the Netherlands, the United Kingdom, and Japan had taken a series of measures to address the challenges posed by climate change on the design of extreme rainfall and floods. They had also formulated corresponding policies and standards, which could provide valuable experiences for other countries.The research findings and current application status of flood standard selection and climate change adaptation policies in several typical developed countries, including the United States, the Netherlands, the United Kingdom and Japan, were systematically reviewed. The policy formulation process and standard selection methods of these countries were comprehensively analyzed from two perspectives: engineering design flood standards and basin flood management standards. Moreover, the specific strategies and measures adopted by the United Kingdom and Japan in response to climate change impacts on extreme rainfall and floods were summarized. The main results were as follows:Federal Emergency Management Agency (FEMA) in the United States had proposed multiple methods for determining flood standards, including prescriptive approach, incremental consequence analysis, risk-informed decision making and site-specific PMP studies. It emphasizes the importance of considering flood potential hazards and risks rather than simply relying on dam size. The Netherlands, through a national flood risk analysis, had transitioned its flood safety standards from being based on exceedance probabilities per year to being based on flood risk. Similarly, the United Kingdom has moved away from using components of the Probable Maximum Flood (PMF) in determining flood standards. Instead, it emphasizes considerations related to potential loss of life, setting high design standards accordingly, often no less than a 10,000-year return period for dam projects with such risks. Meanwhile, in Japan, flood standards are determined through a combination of design rainfall and runoff models. The highest standard ranges from 100 to 200 years, with variations influenced by the dam's material, such as earth and rockfill versus concrete. The United Kingdom and Japan had taken proactive measures to establish comprehensive regulations to address climate change, utilizing future climate projection data to determine the magnitude of changes in design rainfall and floods, and incorporating this information into governmental decision-making and planning processes.In summary, the formulation of engineering design flood standards were mainly reviewed in the United States, the Netherlands, the United Kingdom, and Japan. Additionally, the adaptive strategies formulated by the United Kingdom and Japan in response to climate change were also researched. Based on the analysis and summary of experiences from these countries, the following recommendations were proposed. Firstly, research and application of flood standards was strengthened based on modern risk concepts to make them more scientifically sound. Secondly, a dynamic perspective was adopted to determine flood standards more proactively, considering changes in future socio-economic development. Thirdly, a holistic approach was adopted to coordinate and integrate flood standards across different regions to avoid adverse "risk transfer" effects. Finally, long-term future climate projection data was comprehensively utilized to scientifically assess changes in extreme rainfall and floods and formulate adaptive policies to address climate change. These recommendations can provide valuable insights for the formulation of flood management and climate change adaptation strategies in China's new era, promoting sustainable development in water resources and hydropower engineering.