The purpose of this study was to analyze the contents, functions and necessity of hierarchy of seniority in the A-level university volleyball team of Taiwan. Researchers applied documental analysis, interview and observation to collect the data of eight players and one coach in one team. There were three major findings in this study. First, in A-level university volleyball team, hierarchy of seniority played important role of leadership and management role in training, team affairs, matches and life management. And it would lead to multiform behaviors of social conformity. Second, the interaction between hierarchy of seniority and operation of the team was built up by the tradition of esteem and politeness. Third, the effect of hierarchy of seniority on group cohesiveness was found in this study.