The IMD(International Institute for Management Development) report said that national competitiveness of Korea is declined in this year. The main reason for Korea's decline is a largely related to the weakness of corporate competitiveness. The new product development is a necessary ingredient for improving the national competitiveness. The analysis of changing of technologies and customer's needs is needed for successful new product development. In this paper, We found out successful factors of the project by use of DFSS(Design for Six Sigma) and proved them by case study of K-company. Result from this paper is applied to the new product development planning step for K-company and it made a great success rate. It is expected that the result is applied to the same kind industries.