Abstract in English Family has been the most original economic unit for over 40000 years. However, in the past 30 years family system, population structure, marriage relation, women¡¦s role have been changed. Although marriage has been an important matter since ancient years till today, there are many potential differences between now and then especially in the past 30 years. The structural changes such as external marriage affair, competition between wife and concubine under the wife-concubine system, increasing rate of divorce, and unsymmetrical relation in the essence of marriage can not be simply described or judged right or wrong. Such changes can only be described as a life style, which also is a social culture. However, the increasing impact of such changes cannot be disregarded. This study of this article is on the main axis of marriage system. The article wishes to clarify Chinese marriage system in the past and today from economic perspective and to realize that Chinese marriage system is a collusive structure that has created endless war in a family. On the other hand, this article adopts information asymmetric to interpret matchmaker system that has created many unharmonious couple in the situation that information was not so symmetrical, which explain to us the revenge behavior accounts for the end of marriage relationship. Finally, this article employs economic model in inframarginal analysis and believes there exists many internal-deal expenses in marriage. The modal was further employed to prove that efficiency of matchmaker¡¦s word is higher than free love. In the same time, this article derived that the high expense coefficient of external marriage affair explains why general people are unwilling to try and the employ law to protect. This can reduce such coefficient and remind people of remittal of adultery. Keywords: information asymmetric¡Frotten kid theory¡F adverse selection¡Finframarginal analysis¡Finternal-deal expenses