All corporations have been equalized by the development of technology and it is shown that they have tried to differentiate themselves through their designs. That is, all corporations have started to be concerned about Corporate Identity, Brand Identity and Product Identity for increasing the competitive corporate value as the time of intensely competing in design area had begun. Each corporation represents its own image through products in design and carries out a plan that it actively applies its own corporate culture to management, design, marketing and so on. Among them, it is said that Product Identity has a purpose to establish the identity through a product and it is the most direct strategy that the product is a medium. A consumer directly feels the corporate image by using the product and the communication happens between the corporate image and the consumer when a product is used by a consumer. The corporate can make a good profit through it and it is the purpose of a corporation. Product Identity is one of the most important corporate strategies to lead the communication to a positive way. Therefore, the Product Identity makes the consumer be aware of the corporate philosophy and image through product design and it is important that it gives the same corporate image to all products. The purpose of the study is to understand the meaning and necessity of Product Identity and to know how the Product Identity which has increasing importance affects mobile phones which are delicately and rapidly changing, what elements of Product Identity are important in the case of the mobile phone and what factors are demanded for establishing the Product Identity. For this purpose, the definition, function and necessity of Product Identity are examined through books for reference, and the concept of Corporate Design, Corporate Identity, Brand Identity, and Brand Image, which are related with Product Identity, are analyzed. Secondly, what are the general elements of Product Identity and what are the elements of Product Identity in relation to the mobile phone are surveyed. Thirdly, the elements of Product Identity in mobile phones that the consumers are aware of and concerned about are researched through questionnaires. Fourthly, the Product Identity of the mobile phones of Nokia and Samsung selected according to the result is compared and analyzed in the axis of time and space. Fifthly, a process model is suggested for the powerful Product Identity of a mobile phone according to those results. The results of the study can be summarized as follows. Firstly, the consumers are aware of the first visual Product Identity of a mobile phone among many elements of the Product Identity and it includes the type, the general color and the whole form of the mobile phone. Secondly, Nokia established its own communication way on the basis of form and has a powerful Product Identity different from other competitors according to the result of comparing and analyzing the Product Identity of Nokia and Samsung centered on the axis of time and space in the basis of type, color and form of mobile phones. On the other hand, Samsung makes an experimental design for the recent trend focusing on the type of mobile phone among many elements of Product Identity. The type of mobile phone, however, makes no difference from the type of other competitors and Samsung has less competitiveness. Finally, in order to achieve a powerful Product Identity of mobile phones according to the case study of Nokia and Samsung, the corporate Product Identity must be most effectively represented and then the form must be focused based on the Product Identity which gives a difference to the corporation. In the case of a mobile phone which is sensitive to trend, it is hard to keep the same form without any change but the change without consistency finally creates the loss of its own Product identity. Product Identity is not just a design but an absolute factor which affects all processes including product manufacturing, marketing, consumer needs and so forth. The success of Product Identity cannot be done in coincidence, and the development of Product Identity is very important to the corporate purpose and brand strategy. Accordingly, each corporation must keep and develop its Product Identity through tactical and strategic policy in the consideration of a reasonable design. When a corporation establishes its own Product Identity and communicates it to consumers they can make an ideal product.