This paper studies the process of wh-word movement in Persian according to the universal principle of Move-a, based on the Government-Binding Theory (Chomsky, 1981, 1986). The analysis centers on the optional movement of the wh-word in simple, embedded, and complex interrogative sentences. In this analysis, the principles and syntactic conditions ruling over this syntactical process are determined. Next, the occurrence of the wh-word movement and its A/non-argument nature are substantiated. Also, on the landing -site of wh-word phrase the onset of sentence is demonstrated to be the most suitable and economical syntactical position for the wh-word to attach to in simple and. embedded Persian sentences.