The communication of ideological and political education has such function as feeling expression,cognition communication,education influence,directing and controlling,stimulation and cohesion.To guide the communication function expansion of ideological and political education by using group interpersonal interaction theory is to direct expression and exchange of ideological and political education communication by taking cooperation as the goal,to adjust controlling and leading of ideological and political education communication by using conflicts as the device,to improve stimulation of ideological and political education communication by using hints,imitation and influence.Thus,we should build a benign group interaction order to create an environment of communication function expansion,innovate the group interaction teaching mode to set up the platform of communication function expansion,and utilize the rules of interpersonal relationship to establish a long-term mechanism of communication function expansion.