This report presents the process of conserving, restoring scientific works, as well as ensuring the method and principle of conservation. Besides, because there are many reasons, the restoration of the relic is not currently carried out in accordance with the current regulations and there are some mistakes in the conservation and restoration of the relic. Therefore, understanding the restoration process is the core scientific basis for proposing effective conservation projects and solutions. Moreover, the content of report provides more the materials, and scientific foundations for conservation and restoration of the relic as follows: - Understand the valuable aspects of the Ngo Mon relic; - Help conservationists grasp some methods to identify the relic including analysing history, and construction schedule of the work; analysing actual state (architecture, materials, fine arts...); analysing documentary photos; analysing similar works. - Support people who work in management, project planning, construction of the relics grasp the order, process, regime, and policy of the State when implementing a project to conserve and restore more professionalism.