In order to solve the problems of general loss and difficulty in operation of iron and steel industry, this paper analyzes the various problems facing the cost accounting of iron and steel industry, and puts forward the necessity of implementing the new system accordingly. Then the basic steps of the cost accounting system in iron and steel industry are described in detail, and the superiority of the new system is explained in view of the existing problems in the industry, and the activity-based costing method, which can be used selectively, is put forward. Finally, it explains the influence that the new system may have on the steel industry and the fact that enterprises must treat this phenomenon dialectically in the face of the new system if they want to improve the severe situation at present.