Product family is a series of products with similar characteristics. It is a strategy used by modern enterprise to achieve product diversification with limited development, manufacturing and service. Product DNA is the design commonality of enterprises product family, it is distinctive and aesthetic by reflecting the company's brand value and design concept, in addition ,it include some essential elements such as form, color, material and composition. This paper introduces the methods of drawing product DNA and analysing the relevance of design features to brand style by case study.