social accounting matrix of year 2001 in which parameters of model were calibrated accordingly. Three scenarios were examined: import tariff rate reduction on 1) agricultural sector, 2) non-agricultural sectors, and 3) all sectors. All scenarios result in overall economy-wide welfare with respect to the base. The EV increased by nearly 65, 3047, and 3112 billion rials in scenarios 1, 2 and 3 respectively with 100% reductions on import tariffs.JEL Classification: I31 ،R13 ،F13 ،C68. Nation Economic Firms Evaluation with Membership in the WTO: Determination of Comparative Advantage (DRC), Competitive Advantage (UC) And Supporting Coefficients Analysis (Case Study: Ahwaz Pipe Mills Company) Khadijeh Nasrollahi, Ph.D Mahsa Qandehari, M. A. Omid Boyerhassani, M. A. Student Globalization / Comparative Advantage / Competitive Advantage and Supporting Coefficients / Steel Industry / Ahwaz Pipe Mills Company One of the industries that may strongly be influenced by the globalization process is the steel industry. The present study sought to investigate the effects of globalization on this industry in Iran. In general to investigate the consequences of entering the World Trade Organization on Ahwaz Pipe Mills Company several indicators and methods have been used. In this way, by using the concept of comparative advantage, competitive advantage and support coefficients analysis the consequences of entering the WTO organization on pipe factories (1, 3, 4) and cover plants (1, 2 and 3) have been discussed. The results indicate the high Comparative advantage of the pipe factories (1, 3, 4) and cover plants (1, 2 and 3) both. While the pipe factories (1, 3 and 4) has the 2 Iranian Journal of Trade Studies competitive cost advantage less than that of the cover Plants (1, 2 and 3). Also there are less support for the cover plants sector both in nominal and effective terms