Abstract: Landslide-dams and associated lakes occur in many places around the world, which create natural reservoirs with their occurrence. However, they can cause great damages as floods break them or cause excessive overflow. Historically, some of them have broken quickly, while others could exist for a long time, and can create beautiful landscapes and/or hot spots for tourists around them. They can also help in the development of sustainable water resources. Landslide dams can be classified as three types: landslide dams, rock fall dams and debris flow dams based on their genesis. Because the life of a landslide-dam is determined by its genesis, it is very important to understand its genetic mechanism in their utilization. The paper analyzed the genesis of a landslide-dam, which was formed by slides from both its left and right banks. Because such a dam has been reported rarely, the results presented in this paper will provide a good guideline for future investigation of similar projects.