We can study and judge the costumes of the Three Kingdom period through an ancient tomb murals and various burial mound(clay) figures, however, it is quite difficult to search for costumes of the Goryeo period ($960{\sim}1392$), because dresses from this era were rarely found, related antiquities are limited and hard to survive. This is the reason why people say that the Goryeo Dynasty is the period of undiscovered era for its history of costumes in Korea. Fortunately, these days, there are various kinds of buddhist statues discovered with its burial accessories such as costumes and dyed fabrics of the Goryeo era. Through these, we can glimpse through the Goryeo cloths and develop our researches on this field. In addition, a man called Seo Geung(서긍, the Chinese scholar Xu Jing) wrote a book in the 12th century about peoples lives in Goryeo and in this book, there are few documents about the people's costumes which help us to understand the period's traditional dresses. In this paper, we will look for the traditional costumes which were formed and developed through people's lives in Goryeo, using remains from various burial accessories in buddhist statues as well as the documents related to the costumes written in ${\ll}$Goryeosa 고려사${\gg}$. Moreover, costumes of a period usually developed and influenced by the atmosphere of people's lives both economically and mentally, therefore, in this study, we will especially focus on the dresses of the bureaucratic officials and their wives, who led comfortable lives and latitude of mind. Through the records, like Silla, Goryeo exported Sehjeo(세저) and Sehjoongmapo(세중마포) to China. And we found out that Silla's skillful weaving techniques of hemp and ramie cloths were succeeded to Goryeo. According to above facts, Goryeo people made clothes with various kinds of fabrics such as, different sorts of silks, ramie, hemp cloths and cottons. They also have very skillful manufacturing techniques for certain textiles. Their official robes were generally influenced by Tang and Song Dynasty, but, like ordinary people, we found out that the government officials also wore baji(pants) and a jeogor(jacket), which were traditional costumes since the Unified Silla Kingdom with various coats. Especially, women's costumes such as jeoksam(unlined summer jacket) and hansam(한삼), which are sort of jeogori(jacket), baji(pants) and chima(skirts) were made of various kinds of silks and ramie cloths, that were generated from the Goguryeo Kingdom, with jikryeongpo(a long jacket and striped skirt).