In order to present the actual situation of dam removal in the United States of America(USA)comprehensively and objectively, a reference search and a special survey were carried out. Based on a review of the background and status of dam removal activities, the causes for dam removal in the United States were analyzed, namely environmental, safety, and economic factors. The cases study shows that dam removal in the USA aims to eliminate the safety risk of aging dams, restore anadromous fish migration, and save non-cost-effective expenditure. Dam decommissioning is an important stage in dam lifecycle management. Dam removal in the USA does not operate with the belief that dam construction is unnecessary. Currently, hydropower remains the largest renewable energy source in the USA. The concepts and experience of dam decommissioning in the USA can provide references for reservoir demotion and retirement management in China.