Abstract: Mediation is a democratic and consulting system of resolving dispute.This decides that the method by which folk law enters the mediation must be the choice of litigants.However,the behavior that litigants choose folk laws can not defy or avoid coercive state laws,can not defy communal order and good customs or do harm to the national interest and right of other people.Except these,in the mediation folk laws can change or even replace state laws.