Energy, water, and the environment have remarkably complex interrelationships, with these linkages being both direct and indirect. The innovative development of artificial intelligence (AI) technologies brings significant opportunities for investigating renewable energy (RE), water, and the environment and presents a multitude of challenges. Using AI to promote sustainable production and consumption of RE and water and protection of the environment has become a hot research area that enables AI to empower sustainable human development and promote its own sustainable development. However, there are few summaries and analyses of studies on the application of AI to RE, water, and environment (REWE) nexus. The objective of this chapter is to discuss the application of AI to the REWE nexus. First, this chapter presents and analyzes the AI techniques that are applicable to RE, water, and the environment fields, respectively, and categorizes and integrates them. Also, the chapter summarizes AI application in the REWE nexus. Furthermore, the chapter analyzes the application feasibility of AI for establishing city-level REWE nexus studies and identifies challenges and barriers to their implementation. Finally, the chapter presents the future perspectives for the application of AI to urban-level REWE nexus.