Makinguseof16748exportdataof168countries，thispaperdecomposesexportintoextensive margin and intensive margin，finding the tunnel of the steel export increas. This paper analyzes the factors that have infl uence on export margin. The results indicate that the infl uence of intensive margin is larger than extensive margin，the trade price does not decrease with the increase of export and the infl uence of countrysizeandtradecostis remarkable，butthedegreeofinfluenceis different.