Emotional dialogue technology focuses on the “emotional quotient” of conversational robots, aiming to give the robots the ability to observe, understand and express emotions as humans do. This technology can be seen as the intersection of emotional computing and dialogue technology, and can simultaneously consider the “intelligent quotient” and “emotional quotient” of conversational robots to realize spiritual companionship, emotional comfort, and psychological guidance for users. Combined with the characteristics of emotions in dialogues, this study provides a comprehensive analysis of emotional dialogue technology: 1) Three important technical points including emotion recognition, emotion management, and emotion expression in dialogue scenarios are shown, and the technology of emotional dialogues in multimodal scenarios is expanded. 2) This study presents the latest research progress on technology points related to emotional dialogues and summarizes the main challenges and possible solutions correspondingly. 3) Data resources for emotional dialogue technologies are introduced. 4) The difficulty and prospect of emotional dialogue technology are pointed out.