In the Spanish oblique relative clauses, the definite article between the preposition and relative pronoun is not allowed to appear in some contexts. However, there have been neither rules nor explanations about this phenomenon, so Korean students learning Spanish as L2 have a lot of the difficulty of determining what condition can place it in the oblique relative clauses.In order to resolver this syntax problem, I try to suggest grammatical intuitions about the presence and absence of articles in the oblique relative clauses from the point of view generativist, specifically taking into account the theory of Barriers proposed by Chomsky and Lasnik (1991).This work finally is able to explain a syntactic restriction: if the preposition of the oblique relative clauses may be interpreted with lexical definitions, the definite article must be allowed to appear between the preposition and the relative pronoun, whereas if the preposition is not interpreted with those proper definitions, it is not permitted to put any particular article between the preposition and relative pronoun.