This study aimed to investigate language socialization of affect in Mandarin parent-child interaction. Natural conversations between Mandarin-speaking two-year-olds and their parents were analyzed, focusing on the lexicon of affect words and the conversational interactions in which these words were used. The results showed that the children tended to use the type of affect words which encoded specific affective states, with the children as the primary experiencers. The parents, on the other hand, tended to use affect words not only to encode affective states but also to express evaluative characterizations. They often used affect words to negotiate with the children the appropriate affective responses to a variety of stimuli or to socialize the children’s behaviors into culturally approved patterns. In addition, it was found that the structure of conversational sequences served as a discourse-level resource for the socialization of affect. The findings were further discussed in relation to Clancy’s (1999) model of language socialization of affect.