The study analyzes the costumes of each character of Stephen Frears` "Dangerous Liaisons" which is the remade version from 18th century French novel "Les Liaisons Dangerous" and Milos Forman`s "Valmont" from the viewpoint of 18th century`s Rococo fashion history. On the basis of the analysis, the costumes that suit the characters are designed and are made into modernized forms, The Purpose of the study is to realize the importance of the movie costume. For this purpose, a careful look on the significances and role of the movie costume was taken, each work`s synopses, plots, and the characters were searched, and the 18th century costumes of the two movies which share same periodic backgrounds were analyzed. The analysis of the costumes of both movies is as follows. Firstly, movie costumes help the development of the story and express the personal characters of the personages which lead to elevate the confect and dramatic effects, Secondly, the 18th century, which was the Periodic setting for both movies, was dominated by French ideology. It was the age of the Enlightenment which provided the principles of French Revolution End was in vogue of Rococo style inclined to Baroque style. Thirdly, "Dangerous Liaisons" was appraised to be a well expressed work of Rococo style costume, winning the Oscar prize for costumes design.