The aim of this paper is to investigate the basic Persian word order. According to the Greenberg`s universals on word order, Persian shows two different characteristics, which are head-initial and hear-final. SOV order in simple sentences as well as the existence of postposition represents that Persian is a head-final language. On the other hand, Persian complex sentences which contain relative clause characterize that Persian is a head-initial language. Moreover, the fact that Persian has prepositions and head nouns precede their modifiers in this language represent that this language is head-initial. To handle this complexity, this paper accepts the Kayne(1994)`s theory, which claims that all language in the world have head-initial order in their deep structure. By following the theory, we can explain the Persian basic word order in more consistent and economical way.