In Persian language and generally in all other languages connectives are considered among the most important devices in the coherence of texts. However, there are some other elements such as adverbs and prepositions that operate in the text and function like conjunctions. These are only a few of the elements that connect sentences in a text to each other. We can classify these elements from different perspectives. One of these perspectives isHalliday’s functional theory. In his theoryHalliday calls the semantic, verbal, syntactic and logical connections of the sentences in text coherence. From this point of view, in addition to connectives, the other factors that affect the coherence of the text are reference, displacement, elision, and lexical cohesion. Because of the extent of the subject, the researchers in this article study only one of these factors, namely connection. Among different factors of connection, only non-temporal connectives that include simple, compound, explicative and allegorical connectives; contrastive connection factors including simple and compound connectives; and causal connection factors such as the common and reverse will be studied.