This paper introduces reformation and design of optimizing furnace volume ratio for a 15t converter.If the furnace volume ratio is improved,the output will grow greatly,metal splash is reduced,the consumption of iron and steel materials is lower,the proportion of the blow loss is also cut down,smelting period is shortened,and the quality of steel is improved.The deformation of the furnace shell is small,and the design of the strength of the bracket ring and gudgeon can meet the production request.