In 2008 and early 2009, Phu Yen Provincial Museum in conjunction with the Department of Archeology, University of Social Sciences and Humanities - Ho Chi Minh City National University conducted exploration and excavation the ancient Citadel of Ho Dynasty. Since September 5, 2008, An Tho ancient citadel has been excavated. After nearly 2 months, the excavation ended successfully. This book is a scientific report of that exploration and excavation, including the following main contents: 1. Geographic location - The process of studying Ancient Citadel of the Ho dynasty. 2. Exploration and archaeological excavation of the ancient Citadel of Ho Dynasty for the fourth time. 3. The relics. 4. Ancient citadel of the Ho Dynasty in the context of Champa ancient.