With the rapid development of smart distribution networks and microgrids, it is highly necessary for optimized operation and management by using AI technologies, as intelligence is the inevitable trend. This paper elaborates on the AI-driven optimization technologies for smart distribution networks and microgrids; it introduces the definitions, architectures, and coordinated operation modes of the two technologies; and it details the applications of artificial intelligence technologies such as machine learning, deep learning, and reinforcement learning in power grids. In addition, this paper elaborates on and analyzes the AI-based optimization methods for key technologies such as load forecasting, equipment condition monitoring, topology reconfiguration, and voltage–power control, as well as the key issues in microgrids including distributed energy management, energy storage control, and dynamic coordinated optimization.