The purpose of this study is to find the syntactic rules within adverbial clauses of Yuneum eonhaebon in Joseon dynasty. This paper can be summarized as follows. The basic structure of the adverbial clause is classified into transitive verb, intransitive verb and adjective. The predicate in the adverbial clause can be classified into adjective and verb. The adjective can be classified into ‘judgment adjective’, ‘feeling adjective’ and ‘form dimension adjective’. The verbs are relatively selected to a small number than adjective as the predicate in the adverbial clause. When the verb is the predicate in the adverbial clause, most of the structures are causatively ‘-ke h∧-’ pattern. This is because Yuneum eonhaebon is documents for command. Adverbial endings in the object of study are ‘-t∧s, -torok, -ke’ and ‘-i’. When the predicate in the adverbial clause is judgment adjective, the ‘-i’ adverbial clauses appeared overwhelmingly in Yuneum eonhaebon. It seems to be due to the conservatism of royal courtly language.