The international trade mechanism with the carrier of GATT/WTO directly influences the international trade and macro economy; meanwhile, it also has a profound impact on the non-state actor below the national level. The issue of infant mortality is an important research issue in hygienic economy. It is shown in the former researches that the infant mortality is mainly influenced by the economy, politics, hygienic environment and natural disaster. And this paper studies the interactive relationship between the trade mechanism and public health within the globe and finds that the maturity degree of international trade mechanism influences the infant mortality. This paper chooses the panel data of 177 countries from 1970 to 2009 and takes the successive entrances of member countries to GATT/WTO as the representative variable of the maturity degree of international global mechanism under the time sequence; then it prevents endogeneity using the quantization method of regression discontinuity(RD)and controls 11 variables represented by the governmental quality index, inequality index of family income, unemployment rate, GDP per capita, globalization index, natural disaster index etc. Finally, it draws the conclusion that if the year when each member country enters GATT/WTO is regarded as the “breaking point”(which means “discontinuity”), the infant mortality of each country is quite different before and after the breaking point and it has the obvious tendency of ascending and descending in time sequence. The research finds that when the international trade mechanism is at preliminary maturity stage, it will have “non-compatibility” to the price of medicines in underdeveloped countries due to the obvious increase of fluidity of elements such as healthcare and hygiene, which will lead to the obvious increase of infant mortality; with the gradual maturity of trade mechanism, the non-compatibility will reduce and meanwhile the mortality will also decrease.