Digital media has unprecedented features of interactivity, portability and multimedia, which creates a new communicative situation for our interpersonal interaction and reconstructs the current model of family and social relationships, compared to traditional media of interpersonal communication such as telephones, letters, etc. In the process of building this new model, "emerging adulthood" is a very crucial period. Based on the interviews with parents and children and communication privacy management theory, he study uses the grounded theory method to explore the process and effects of communication between the emerging adults and their parents who communicate through WeChat, QQ and other digital media while they are separated geographically. During the process, the children and their parents focus on the boundaries of privacy to interact, negotiate and adjust each other while the digital media has played a signifcant role. This study puts forward the theoretical framework of the process of family communication, and illustrates this process initially on the basis of communication privacy management theory.