A new Hanoi city had been expanded over 3,300km2, which merged the old Hanoi
with Ha Tay province and parts of Vinh Phuc and Hoa Binh provinces from August 1, 2008.
After more than 10 emerge years, the population in the new city has gone up to over 8,05 million
people in 2020. Improving urban living environment is one of the important targets for the new
Hanoi, and managing open-space (m-OS) is a key element in achieving this goal. M-OS is a
crucial issue since the expansion and re-zoning of the city can increase the rate of urbanization,
cause disappearance of open-space and lead to a serious deterioration of living conditions.
Administratively, institutions need to be reformed to effectively manage open spaces in the
expanded Hanoi and there is a need to implement specific strategies to manage these areas. This
paper aims to provide a solution in managing open-spaces. A managerial model consists of
regulatory simplification and adjustment, decentralization of decision-making and simplification
of open-space management process. Lastly, proposing an active plan is necessary to implement
such strategies successfully and ensure effective and efficient management of open-space and
community participation for a mega- Hanoi.