With the development of mobile technology, customer-centered co-design modularization (CCCM) has been studied by researchers and brand operators. In contrast, in the field of skirt design, CCCM on mobile application has been largely ignored. The purpose of this study is to develop a customer-centered co-design modularization on skirt that enables customers to co-design skirt on mobile application. On the basis of analytic hierarchy theory and interactive genetic algorithm, CCCM is consisted of two categories, such as skirt parts (design attributes) and communicating parts (behavior attributes). Skirt parts are determined by knowledge classification. Communicating parts are supported by recommending, consulting, evaluating among customers, consultant, and expert. The customer-centered co-design modularization was conducted and proved by a mathematical model. Compared to online shopping, the proposed CCCM is a good approach to involve stakeholders (customer, consultant, and expert) to design together who can communicate on mobile application.