The social network site, Facebook allows consumers to present themselves, articulate their social networks, and establish or maintain connections with others. This study focuses on Facebook user and explores what is the influential mechanism of the process that consumers expressing their self by sharing brand message on Facebook. The current study used an online questionnaire to conduct empirical research, and collected and analyzed data of 508 samples by hierarchical regression approach. The findings show that the needs for self-expression on Facebook and brand engagement in self-concept (BESC) have positive effect on their need for self-expression through brands. Furthermore, the degrees of self-expression through brands have positive effect on brand sharing intention.