The NAISIDA team provided constant temperature and humidity control services for the Taishan Nuclear Power Plant Phase I and Phase II project. The site is a new air duct gas temperature control and dehumidification. When fresh air enters the pipe, it also introduces outdoor high-temperature and high-humidity air into the pipe, causing pipe welding personnel Difficulty of work and rust on the pipe wall affect the progress of the work; combined with the site, our company provides professional technical solutions, recommending the use of a new air combined rotary dehumidification unit with an air volume of 4500m³/h, using a front desuperheater, and a rear runner to dehumidify. After the cooling process, after the installation, the pipe air supply index is stably controlled at a temperature of less than 20℃ and a humidity of less than 40%RH, which can meet the air drying value in the pipe and greatly improve the work efficiency of the welders.