The invention provides an activity recommendation system and an activity recommendation method based on an online and offline double social relation, and belongs to the technical field of friend recommendation of a social network site. A target user potential friend discovering strategy is realized by utilizing an online same-group and off same-activity double social relation, and an available implementation method is provided for transplanting the traditional activity recommendation algorithm to an EBSN (event based on social networks) recommendation system; an activity that the target user is interested in can be recommended to the target user accurately based on the activity preference of the target user potential friend discovered by the invention, and the service quality of the EBSN recommendation system is improved; the invention also provides a user social activity statistical analysis function, the social activity statistical analysis result of a region can be shown in the form of a visual friendly interface and according to the region that the user selects, and information support with reference value is provided for other applications.