This qualitative study explored eight 4-year-old children’s peer conflict during pretense.  Based on Bateson’s (1972) idea of metacommunication and Goffman’s (1974) frame theory, the researcher found that whether to be in-frame or out-of-frame to negotiate conflict was closely related to the following features: nature of pretense, pretend phase, number of oppositional turns, discourse skill, goal of peer interaction.  Most conflicts occurred in socio-dramatic pretense and during dramatization phase.  They often caused children to step out of pretend frame.  Those who shared understanding about pretense, including collaborative and parallel players, could metacommunicate longer in-frame. The more oppositional turns were exchanged, the less engrossed children were in pretense.  Children applied a variety of discourse devices, such as “pretend”, “right”, and “too” to evoke comradeship, integrate different opinions, transform symbolic ideas, mutually aware while monitoring each other’s mind.  The findings inspire preschool teachers to recognize the characteristics of peer conflict in children’s pretense, as well as appreciate its significance in the development of pretend play and metacommunicative abilities.