Current studies on Hanshan poetry more confine themselves to interpretations of Zen's remarks and poems, and yet fail to make an integral analysis of the background of Hanshan poetry, that is, the intellectual history of Zen School and its specific developments. Through a study of mutual interpretations between Zen School's historical materials and poems, this paper concludes that as a generation Zen's literature, Hanshan poetry implicitly displayed the Tang-dynasty Zen School's two major sects' rise and fall.