Abstract: The appearance of "four styles and two application theory" of the Six Books was not the achievement of DAI Zhen himself.In fact,it was not put forward by DAI Zhen for the first time,and it actually experienced a process of originating,forming,precise explanation and systematic application.XU Kai,ZHENG Qiao and DAI Tong together started the study of this theory,ZHOU Bo-qi developed it and WU Yuan-man and YANG Shen constructed its frame.Then DAI Zhen precisely and systematically explained it and D...