While it was found that consumers’ experience on purchase intention is significantly affected by greater involvement in blogging (Hsu & Tsou, 2011), not many fashion companies use blogs to improve online consumption and relationship with their employee or customer (Fieseler & Fleck, 2013). Further, despite the growing significance of blog communication, there is a lack of understanding for the impact of accumulation of social capital in the blogosphere on the consumers’ attitude and engagement in previous research. This study is designed to address this gap, and particularly the role of three dimensions of social capital (i.e., structural, relational, and cognitive) in understanding blog user’s attitude and engagement. The purpose of this study is to investigate 1) the effect of blog user’s motivation (i.e., perceived usefulness, perceived ease of use, reputation, altruism, enjoyment, community identification) on their level of social capital within the blog 2) the influence of structural social capital and cognitive social on user’s relational social capital and 3) the impact of relational social capital on blog user’s attitude and engagement. Data was collected through a marketing research firm utilizing online survey method. With 530 usable data, the results of this study indicated enjoyment have positive significant effect on structural social capital while community identification have negative significant effect on structural social capital. For the effect of blogging motivation on cognitive social capital, the result showed positive significant effect of perceived usefulness, altruism and community identification on cognitive social capital Further, structural social capital does not have relationship with relational social capital while cognitive social capital has significant effect on relational social capital. The results also indicated that the relational social capital has influence on blogging attitude, which in turn has strong positive relationship with blogging engagement. The findings of this study contribute some useful knowledge about fashion blog and the relationships of the three social capital dimensions to the literature. Also, this study not only provides theoretical insight into understanding the influence of fashion blog user’s motivation on blogging behavior and satisfaction of needs of belong, it also exposes the influence of relationships building in blog community on user’s blogging attitude and engagement. Previous studies focused more on social influence on knowledge sharing motivation, and most of the researchers paid attention to the interaction of cognitive social capital and relational capital. This study employs the knowledge sharing motivation findings of previous studies, and it uses the effective motivation factors to test if they have the same impacts on people’s blogging behavior.