The existence or abolishment of adultery has been a dispute in academic circles for a long time. Though, it is permissible under the Constitution, according to the Constitutional Interpretation 554. However, many domestic law scholars and feminists argue that adultery should allow to be decriminalized from the perspectives of proportional principle, balance of criminal law¡¦s interest and comparative legal institution. This dissertation analyses the crime of adultery in current days via a newly emerging research approach, namely legal economics. To begin with, I clarify and confirm the legal interests in which marriage and family institutions are involved, that is to say the right of family, whom the crime of adultery in criminal law protects. Taking them as a analysis benchmark, and apply them to be the criterion on the assessment of crime of adultery thereafter. Then, use the concepts of demand, cost and benefit as tools, analyze the feasors and victim of adultery comparatively on the basis of the practice of current prosecution and judgement. The analysis shows that the norms of current crime of adultery couldn¡¦t objectively prevent it from happening. Moreover, it is a burden for the victim wife to start a lawsuit. The advantages obtained from criminal lawsuit could simply be retrieved from claim right in civil code. Besides, lawsuit started by victim wife always lead to family disharmony which at the same time contradicts the benefit of family right entitled by the crime itself. It infers that the crime of adultery should be discriminalized. During the research process, I also analyze the philosophical essence and theory of legal economics, which affirm the legitimate application of economics on law research. Will it lack protection on marriage and family institution after crime of adultery being discriminalized? The article considers this in a view of basic rights protection in the Constitution. How could we fullfil the protection through the law of a lower-level after the crime of adultery being recognized as the protection of family right, which at the same time the basic right the Constitution protects? After summarizing perspectives of theory and practice could be divided to the one that involves the conclusion of marriage, the termination of freedom and monogamy as a narrow interpretation of family right, and nurturing teenagers and protecting family members as broad interpretation on the other. Thus, the way of legalization should be different due to the distinction of broad and narrow family right. As to the narrow family right, it should focus on protection of the right of freedom. In addition, according to the rigidity of criminal law, especially being reviewed by proportional principle, there should be no need to limit the execution of freedom right, when it involves adultery, a stronger behavior in ethical level. Therefore, the existence of crime of adultery is unnecessary. There is a necessity that the Constitution Interpretation 554 needs to be reviewed. However, as far as the broad interpretation of family right is concerned, the criminal law couldn¡¦t force people to accomplish certain do¡¦s and don¡¦ts if it makes great damages to human dignity or jeopardizes the continuity of personality and family.