Based on the harm of NOx and the national environmental protection policy, the selective catalytic reduction (SCR) de-NOx reconstruction project was implemented in Huaneng Fuzhou Power Plant. This paper introduced the difficulties and characteristics of the project’s design and construction, such as the engineering steel structure, the SCR denitration device, the storage and preparation system for reducing agent, the injection and mixing system of ammonia/gas, and so on. Moreover, the design and construction problems were analyzed, and some suggestions were put forward, which could provide an important reference for other de-NOx reconstruction project in coal-fired power plants.