The change of various paradigms, development of technology, and development of design have brought lots of changes from method to reproduce form to form composition. This development has assigned possibility to express various designs to designer, and many informal designs had appeared, accordingly. Therefore, we think that it requires study on classification of method to express informality as tool of design representation, and characteristic to form, so we have studied on formal expression of informality and design characteristic in Victor & Rolf. collection in this study. The result of study is as follows; First, as for expression type of informality, extracted based on advanced research, it can be divided into distortion, expansion, overlay, and asymmetry. For distortion, omission or repetition of specific areas, position of design element, or contradictory combination is shown to be deformed in Victor & Rolf. collection. As for expansion, it has appeared as silhouette of clothes or detail, expansion of bodily element, and form of emphasis. With respect to overlay, it is shown as transparency in overlapping, detail of repeated form, and utilization of material, and represented informality for asymmetry aside from traditional principle of composition, by generating new formative beauty by form of unequal disharmony. Second, the characteristic of informality extracted from Victor & Rolf. collection, based on expression type of this informality, is dynamic, unpredictable, playfulness, and experiment. Dynamic is shown by attached frill and flounce as overlapped form, asymmetrical form of both sides, and expanded silhouette. Concerning unpredictable, it is found as unpredictable form of clothes by distortion and deformation of design, mode of wearing, and unpredictable surface effect of clothes. Also, it has provided aesthetic playfulness to deformed, expanded, exaggerated, and distorted design. Lastly, for experiment, it is emerged by pursuing realization of various images, along with fragmented and antiform character, aside from existing universal framework. Based on result of above study, we hope that follow-up study on informality with infinite possibility and potential will be activated, by tool of expression for new design.