The purpose of this study is to the effect of local festivals' brand on the regional image and development. The literature and empirical studies were done together to accomplish the purpose of this study. The literature study composed factors based on the precedent studies about local festivals' brand, the regional image and the regional development and set research models and research hypotheses. In the empirical study, the survey was intended for visitors of Muju Firefly Festival by developing the questionnaire based on the factors which were drawn based on the literature study and frequency analysis, factorial analysis, reliability analysis and multiple regression analysis were carried out using SPSS 18.0 Statistical Package for data analysis. The main analytical results of this study are examined as follow. The effect relationship of the local festivals' brand on the regional image was analyzed that the festival's contents and convenience have the significant effect on the regional image. The effect relationship of the regional image on the regional development was analyzed that the regional images have the significant effect on the economic, social and cultural and tourist effects. Third, the effect relationship of the regional festival's brand on the regional development was analyzed that the festival's contents, convenience, preference have the significant effect on the economic effects and its convenience, uniqueness have the significant effect on the social and cultural and tourist effects.