This paper investigate into a hypothetical concept of 'multi-audiences' and composition teaching method by using it. A hypothetical concept of multi-audiences draw on that the voices of discourse community, social level audience, are multiplex and the voices of audience which cope with writer's multi-voices are multiplex. Its concept is useful to solve the problem of audience inconsistency in composition education. In the concept, the appearance of audience inconsistency is not problem but nature of composition. Therefore, this paper propose three teaching method of composition through multi-audiences follows : first, a method of systemic statement in composition task to muti-audiences, second, a method of peer writers were took as multi-audiences in peer evaluation-response activities, third, through using across curriculum writing content area teacher and writing teacher are regarded as multi-audiences.