Brand royalty is an important issue in the competing marketing environment. Brand royalty always is the important asset of company. Especially for a product, how to maintain the value of brand, and to promote the brand, depends on customer's brand loyalty. There is no any extant literature focus on the perspective of customer-salesperson relationship. Therefore, the purpose of this study is to provide a casual model to explain the effect of customer's likability of salesperson on brand royalty. The results indicate that higher customer's likability of salesperson will increase customer's perceived trustworthiness and perceived expertise of the salesperson, which will in turn increase customer's brand royalty.