Emotion recognition is an interdisciplinary research field which relates to cognitive science, psychology, signal processing, pattern recognition, artificial intelligence, and so on, aiming at helping computer understand human emotion state to realize natural human-computer interaction. In this survey, the psychological theory of emotion is firstly introduced as the theoretical basis for the emotion model used in emotion recognition, including appraisal theory, dimensional models of emotion, brain mechanisms, and computing models. Then, the advanced technologies of dimensional emotion recognition from the artificial intelligence perspective, such as the speech emotion corpora, feature extraction, classification, are presented in detail. Finally, the challenges of dimensional emotion recognition are discussed and the workable solutions and future research directions are proposed.