In recent years, there has been a growing interest in improving all aspects of the interaction between humans and computers. It is proved that to succeed an intelligent interaction between human and machine, computer must be able to interact naturally as possible, exactly like human-human communication. Humans interact specially with speech, but he can add other way like body gestures and looks, to better display its emotions. Emotions can be expressed by visual, vocal, and other physiological means. In this paper, based on body gestures, we discuss a new intelligent approach to detect user emotion.