At present，football 3-5-2 formation is one of the popular lineups of games. It has better effects while competing with other popular lineups. Using referring to documents and data and other ways，this article analyzes three important points of 3-5-2 formation（fielding，attack and the shift between them）and it crystallizes the assignments of power of attack and fielding and the position of division of duty in competition. It also points out the demanding and changes of tactics to the members in the same position in different periods. Therefore，after every member knows his position and main duty，bringing individual wisdom and the whole functions into play and using reasonably，the team can achieve the success of competition，and then get the best efficacy.