Although the scope of Official Development Assistance(ODA) projects has been expanded to the energy and environmental sectors, many Green ODA projects have experienced difficulties in sustainable operation because of insufficient consideration on the real status of recipient countries. Selecting technology to apply is the first step on the ODA process, however, there has been lack of study on evaluation indicators, especially for waste-to-energy. Therefore, we have explored the evaluation indicators for waste-to-energy technologies selection based on the case of Phnom Penh capital city in Cambodia. The study was performed through literatures review, field trips, and interviewing local officials and experts. Finally, we have suggested following indicators: secure of raw materials (waste price, collection, waste quality), sustainable operation (construction and operation cost, land use, management ability), and market condition (prices of substitutes, demanders, required quality of products).