The purpose of this article is to discuss about the characteristics of children’s lying behavior, the causality and prevention and the measurements of guidance. The literature analysis and detection is the major way used by the author. The contents in the study includes six parts as the following: 1.The definition of lying behavior. 2.The ratio of appearance of liar children. 3.The behavior characteristics of liar children. 4.The analysis of causes of lying behavior. 5.The measurements of prevention. 6.The guidance of strategies.