Abstract: The traditional data acquisition method for reactor coolant system temperature measurement channel calibration test（RCP63） is artificial acquisition method. It is with low processing efficiency, prone to human error, poor archiving and other issues. For these problems, this paper studies the DCS（digital instrument control system） data acquisition characteristics of nuclear power plants, and uses the database data in the DCS（digital instrument control system） for data acquisition. The method had been successfully applied to the unit 3 of Hongyanhe Nuclear Power Plant, which increased the work efficiency and reduced the potential human errors.