Based on the previous study on the impact of non verbal communication, this study examined the relative importance of three different aspects of non-verbal communication(i..e, non verbal language, physical appearance, place atmosphere) in determining the relationship quality. It also tested the impact of relationship quality on the brand royalty. Data for this study were collected from 1195 people who were older than 20years and had used restaurants before and during the April 2011 in Daegu City. This study found that out of the three factors of non verbal communication in a restaurant service, non-verbal language such smile on face was the most important factor that determined the quality of relationship between customer and service provider. And, it was followed by physical appearance and place atmosphere. Finally, results showed that the respondents evaluation on the relationship quality made significant positive impact on their brand royalty. Implications and limitation of this study were also discussed.