The Vocative construction is one of the earliest conceptions acquired by children. So it must be a universal phenomenon. It is surprising that it had been rarely studied. While the vocative is a building block of sentences, although non-obligatory, it has often been approached from a non-linguistics perspective. This paper aims to investigate both the internal/syntactic structure of the vocative phrase and its syntactic position in Persian within the framework of Minimalist Theory. To do this, the data are collected addressee, which is identified by the vocative phrase (VocP), is a functional projection derived by a bundle of morpho-syntactic and semantic features. In the one hand, the projection is located above the functional projections of the nominal domain and the determiner phrase (DP). On the other hand, it is located in the left periphery of the sentence. The vocative phrase located between the topicalized and focused phrases as a result of topic and focus movement in the language. The phrase may or may not be co-indexed with a constituent in the main clause. Although vocative phrases are not morphologically marked in Modern Persian, there are elements such as “Ey”, “Âhây” and “hey” which are sign of vocative in Persian, named vocative particles. These particles are optional, however, located in the vocative phrase. The particles, also, are different stylistically. The fisrt one is used in literary style and the second two particles are used in colloquial style. Moreover, the vocative head is shown to take a DP complement. The DP merges with the head of the phrase, as its complement Vocative particles are proposed to bear an uninterpretable D-feature along with the some other morpho-syntactic features. Checking these features make the DP complement to be interpreted as vocative in the LF, namely the vocative DP. The distribution of vocative particles indicates that the “EY” particle is a bound morpheme but “Âhây” and “Hey” are free morphemes. The projection is prosodically marked by pause and linearly followed by a comma