This study examines the characteristics of 45 sects of seven new aboriginal religious groups in Korea including Jeungsan sect, Tangun sect, Soowoon sect, Won Buddhism, Bongnam sect, Gahksedo sect, Shamanism sect through field study and various documents. The purpose of the study is to elucidate how their religious ideas are reflected in their ceremonial costumes and what characteritics and underlying meanings these costumes have, and I reached the following conclusions 1. The new religious groups in Korea modified or mixed the designs or names of existing outfits to convey their ideas or beliefs in their costumes. 2. The costumes of new religious groups turned out to have certain characteristics in common: they all reflected the times, Korean tradition, ancestor worship. 3. I looked at the symbolicity, names, and types of the outfit, and their color scheme to establish their structural characteristics, and it turned out that they an symbolized the creeds and ideas of each religion. The names of the costumes such as Way-Robe, Law-Robe, and Ceremony-Robe, for instance, had to do with Buddhism Taoism, and Confucianism. The most common type of costume consisted of traditional hanbok top, pant, robe, and some type of headpiece for men, and hanbok top and, skirt for women, and if women were to wear a robe, it usually meant the sect believed in sexual equality. There was also a tendency to simplify or minimize the dress code, which seems to indicate that the sect was trying to adapt itself to, the times. The most common type of the outer garment for men was a robe with narrow sleeves, straight lapel, and no slits, and a robe with wide sleeves, straight lapel, and slits for women. The color scheme of the costumes included blue, white, yellow, red, and black, reflecting the influence of the Yin-Yang and Five Elements idea and traditional preference for white of Koreans. 4. These religious costumes were worn at various ceremonies, ritual, and various anniversary services for the master and other dignitaries of the sect to render greater piety to those gatherings, to distinguish the sect from other religious groups, to clarify the meaning of the ceremony, and to heighten the devout feelings of the participants. Thus, the structure (the symbolicity, names, and types of the outfit, and their color scheme) and religious background of the costumes of the new aboriginal religious groups in Korea turned out to have inherited and mixed various element of traditional Korean outfit and those of existing religions to symbolize their religious ideas. Many religions in and fall, and each has its own dress codes, and I hope this study provides a framework and data for other researchers and leaders of new religious groups that will emerge in the future.