Abstract: Starting from the class essence of competitive sports, this paper clearly defines the concept of medium confrontation items and makes the connotation of ball games.By the means of the analysis of historical process, this paper clarifies the relationships among ball game system, origin, genealogy and family, and explores the internal relations between ball classification and family.The research shows that the ball game is equivalent to the medium confrontation item, and it is a sports game that confronts by taking medium body as an instrumentality so as to show essence force of human.Medium confrontation items include“Ju”, two structural origins of big-small“Wan”, three cluster genealogies and nine function families.At the same time, the research results show that the medium dynamics structure and the competitive action feature of different families have category contradictory relationships and is the basic yardstick for the classification research of the ball while the family is the result of self-evolution of the medium confrontation sports.