Beside fascinating landscape, aboriginal culture of Thao had been the important content in tourism of Sun Moon Lake. In history, the tourism development of Sun Moon Lake has had a close relationship with the development of Thao, but it has never been studied completely to know the situation and change between this relitionship. In order to sort out the account of Thao culture in the tourism development of Sun Moon Lake and deeply overlook actual policy proceedings, the study sets the question: "if there is no Thao culture, how about the tourism development of Sun Moon Lake?". By analyses of literatures and In-depth interview, the study found that the tradition and significance of Thao culture has gradually blurred and declined, although competent authorities has regarded it as one important character in tourism of Sun Moon Lake and spent several projects on it. It’ll be a threat for the development of Sun Moon Lake. From the standpoints of culture tourism and culture reconversion, the authority needs to restore the cultural ecology of Thao in order to rich cultural assets for the sustainable development of Sun Moon Lake.