Loyal users of a specific brand sometimes might have negative thoughts about competing brand. Researchers name this psychological phenomenon oppositional brand loyalty. This study employs social identity theory as its theoretical framework to verify the effects of both positive and negative emotions on oppositional brand loyalty. We use a sample of a community which conducts multi-brand discussion inside. Analyzing of 299 valid samples collected, results indicate members who identified with their own online brand community also identified with the brand related to the same community; members with brand identification would further develop self-brand connections; self-brand connections makes members hold positive emotion to favored brand and negative emotion to competing brand; positive emotion to favored brand and negative emotion to competing brand lead to oppositional brand loyalty. Based on these findings, theoretical and practical implications are provided.