There is provided a user interface which enables all users to input a purpose of use of a chromatography data system, recognize a series of operation flow of the analysis of chromatograph data according to the input purpose, improve an operability and prevent an operation error regardless of the user's knowledge on analyzing the chromatograph data or the user's proficiency in the chromatography data system. In a chromatograph data processing, the present invention relates to recognizing chromatograph data analyzing means on a picture and displaying the chromatograph data analyzing means on the picture in accordance with purpose of use. According to the present invention, the chromatography data system can be easily operated regardless of the knowledge on the analysis of chromatograph data or proficiency in the chromatography data system.