Abstract: The shortening of exile distance was first seen in Tang Dynasty,and was developed and institutionalised in line with traditional legal idea such as hierarchical order of penalty,prudential punishment and the perspective of the world.In Song Dynasty,its legal system gradually took shape,which was regulated by legal articles and emperor’s order document.On the basis of the legal institution in Tang Dynasty,Song Dynasty added move method that could be applied for.However,not all exiles can obtain the opportunity to shorten their exile distance through application,as they also need to meet the legal requirements of Subject conditions,statutory sentence and specified period.Those who met the legal requirements will be confirmed by the central and local officials,and then handed over to local officials for execution.It usually move from exile place to the legal center by grade.The rules regarding the center and grade changed in different times.Song Dynasty inherited and reformed the institutional regulations of Tang Dynasty,which reflects the contradiction and compromise between ideals and reality.It also can provide a different analytical perspective on the theory of Tang-Song transition and the history of Exile.