The purpose of this paper is to study the syntactic structure of ‘neo-gi-da’ adverbial clause shown from the 15th century to the early 20th century and to categorize its structure and examine its changing process and lexical features. The main results are as follows: first, its structure is classified to five types including the basic structure which is ‘A가(subject) B를(object) [adverbial clause] ‘neo-gi-da’. The five types have a different syntactic structure depending on the adjectives of the adverbial clause, such as ‘judgement adjective’, ‘feeling adjective’, and ‘psychological verb’. Second, among the five types, the first type, the basic structure, appears most, the second type and the fourth type follows and the fifth type looks more lively in the early 20th century than the third type. Third, the predicates of the adverbial clause are 256 kinds and among them, ‘psychological verb’ increases slowly and ends up with 23 kinds in the early 20th century. Fourth, ‘-i’ adverbial clause modifying ‘neo-gi-da’ has been dominant. However, ‘-ke’ adverbial clause, insignificantly used, has appeared increasingly, finally reached 113 examples(25%) in the early 20th century.