The concomitance of prosperity and poverty come as an enigma in today's world.As some people in this world benefit greatly from advanced technologies andglobalization, others are still suffering heavily from poverty. One noticeable fact is thatalmost all developing countries have their own distinguished "poor area". Such poorareas seem to persist regardless of robust economic growth enjoyed by the overalleconomy.By decomposing the developing country into two regions, one rich coastal regionand one poor inland region, this research establishes a new classical general equilibrium3X2 Ricardian model to investigate how trade liberalization will affect the participationin the division of labor by poor individuals in the inland region in a developing countryand their associated welfare change under different trading conditions.Our model of division of labor on poverty delineates the interdependentrelationship between individuals in the poor inland region, the rich coastal region and thedeveloped country. Market integration plays a very important role in suchinterdependency. Low transaction efficiency is the bottle-neck constraint on the poorinland region's integration into international division of labor through international trade.Thus, it is critical for the poor inland region to improve the market transaction efficiencyin order to enjoy gains from trade.Our marginal and inframarginal analysis show that as an important part of tradeliberalization policy, tariff reduction may not always be a good policy choice for thedeveloping country to alleviate the poverty. Whether tariff reduction makes the inlandregion better off depends on the initial general equilibrium market structure and thedeveloping country's power of influencing its terms of trade. If the developing country islarge enough to determine the terms of trade in international trade with the developedcountry, the developing country may increase the welfare level of the poor inland regionby increasing its tariff rate. But the developed country will oppose it because the tariffrate increase in the developing country will hurt its welfare. Trade negotiation is thennecessary to determine the final tariff rate and the share of gains of trade to each countryand region.

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