DUAN has engaged in academic research and design practice in urban planning and design for more than 30 years. He has constructed the theory and methodology of Urban Spatial Development Theory and put forward the concept of the Space Gene. His innovation in theoretical consideration includes a series of national strategies and major local projects, such as Xiongan New Area, Demonstration Zone
of Green and Integrated Ecological Development of the Yangtze River Delta and Starting Area of Dynamic Transformation Between Old and New in Jinan, against challenges in China's urbanization process, especially the crisis of contemporary cultural identity, tension because of deterioration of natural environment and the loss of historical information.

Furthermore, DUAN has published 16 books as the 1rst author and more than 160 papers. He was honored with 3 first prizes of Science and Technology Process Awards at provincial and ministerial levels (1990, 2018, and 2022), 33 international and national planning and design awards as the first recipient and 18 international competition winners.