The tourism industry is a major driver in improving socio-economic conditions in a developing country. Community-based ecotourism development can serve as the main priority in supporting the development of a region. Community-based ecotourism development needs to get major attention, because ecotourism is an interrelated activity, including with the cultural, socio-economic, political, environmental sectors. The problem to be studied in this research is are 1). What is Banjarnegara Regency Policy in Regional Cooperation towards Management and Development of Dieng Plateau Ecotourism Area? 2). How the impacts of community based ecotourism in Dieng Data collection of respondents is done by interview and questionnaire method and then the data is analyzed by using descriptive analysis. Meanwhile, the community-based ecotourism development plan in Dieng was formulated using the SWOT analysis approach. Development of community based ecotourism in Dieng based on two things, those are 1). Banjarnegara Regency Policy in Regional Cooperation towards Management and Development of Dieng Plateau Ecotourism Area 2). The impacts of Community Based Ecotorism in Dieng. Cooperation between regions is synergistic and in line with the regional planning system in Banjarnegara Regency. Cooperation conducted with Wonosobo Regency is considered to have been participatory by Banjarnegara Regency. This is evidenced by always involving all stakeholders in every coordination meeting in the development of Dieng area. Consist of local government, the society represented by Pokdarwis, as well as from the NGO of Peduli Pariwisata dan Lingkungan. Based on the results of the research, with the activity of tourism in Dieng bring positive impact to the goals of community based ecotorism, those are Psychological, Political, Economic, Social levels.