Many fashion designers have pursued the principle of sustainability to provide clothes that meet consumer's needs and aim to make the major benefits of clothing product and change the wearer's practices in ways to wear and improve the pattern of rapid consumption of less consumption. Transformable clothing is one of the applications of sustainability in fashion design, which can be comfortably worn in multiple ways. It can be transformed into another shape and able to transform back to the original shape by altering its components. The standards of convertible fashion design are flexibility, mobility and adaptability. The standards of transformable clothes are flexibility, mobility and adaptability. Using the modular design system as one of the types of transformable clothes, more than one dress style can be obtained for one clothing product using modules that can be added or removed to the clothing design and inspired by the abstract geometric thought of Mondrian. The present research aims to create fashion designs for women in the age group (18-25 years) inspired by the abstract geometric thought of the artist Mondrian with a new vision as an application of the theory of sustainability using the modular design system, which can be obtained from more than one style to wear for basic design using remove and/or add modular units, and implement them with appropriate implementation techniques. The findings indicate that modular design allows wearers customize the garment into any possible combinations by modifying the modules, so various styles are created from the main design, thus the researchers created three proposed designs. Each design consists of the main design and numbers of modules which can be remove and/or added by using appropriate fasteners.