By taking China as a standard country, this article calculates the relative technical level coefficients of 14 manufacturing industries in 1995-2011 of NAFTA 3 countries and 35 non NAFTA countries by EKS model, empirically analyzes the changes and stages of the relative technological level of NAFTA countries by horizontally time analyzing and vertically inter-country comparison, and draws the following conclusions: Firstly, the establishment of NAFTA benefits all member countries in technical progress, and the relative technical level of member countries' manufacturing is higher than that of non NAFTA countries. This seems to indicate that the establishment of the stronger economic complementarity, inter industry division of the South-North free trade area, better than based on more isomorphism, intra industry division of labor "North-North" regional integration organization (EU) in the manufacturing sector relative to upgrade the technology level, the members can make a bigger profit. Secondly, in the NAFTA member countries, the United States manufacturing sector has the highest relative technical level, but the technical level difference is the largest among all departments. Canada is located in the second, and the level among the departments is different; Mexico is the lowest and the level is not very different. In the change trend, there are similarities and differences between the three countries in technological change, indicating that the establishment of the FTA does not indicate that the technique level of the manufacturing sector of member countries can increase, but produces the division of labor and differentiation in the area. Thus, the Free Trade Area or Free Trade Agreement should not be totally negated because of the downturn of a particular sector. Bilateral or multiple sides free trade agreement or economic integration agreement should be used to break the barrier of increasing trade protectionism, especially China should make economic and trade integration agreement with the countries with strong economic complementarity and high technical level and actively upgrade internal technical level and raise Chinese products position at international value chain.