This study examined the expression characteristics in pop art works of Jean-Charles de Castelbajac. The study here aimed at possibility to find a design development in building up the unique art world of creativity based on popularity, artistry, and originality without confinement to the trend only. For the research method, review of literature and analysis about Castelbajac's works reflecting the pop art feature in the collections from 2000S/S to 2012F/W were performed. The results of research are as follows. The external expression form of Castelbajac's works based on pop art was grouped roughly into use of mass culture image, appropriation of pop art expression technique, and parody of art works. First, his work appeared as application of the mass culture image such as symbolic thing in the modern consumer society, object in an ordinary life, character of well-known animation, national flag and famous star. Second, such appropriated pop art techniques showed as pop color in strong primary color and silk screen, photomontage, collage, assemblage, graffiti, and lettering. Third, a variety of images featured earlier in art works were shown in parody. These works are valuable in that they are expressed aesthetically through regeneration of popular culture's various images in view of fashion, they are described in the non-traditional value with frolic resistance and deviation out of existing fashion norm, and they are given the dynamic creativity integrated with art and fashion.