This study aimed to investigate the quality of interpretation services for tourists who visits in historical sites of Tainan. In this study, "Interpretation Service Quality" and "Loyalty" was applied to measurements collected data and analyzed by regression analysis. The results are following: First, the "interpretation service quality" has a positive impact to "loyalty". Second, the tourists prefer "interpretive signs" than "interpretation of narrators". Based on the findings, the study concluded that the relevant units should strengthen the training of personnel interpretation ability in order to increase tourists' participation and loyalty.