The main characteristic of Hafez style is polysemy of his words. He has tried different ways, especially ambiguity, to achieve this important. Hafez has been committed to creating ambiguity by different methods. One of the ways Hafez has picked for creating ambiguity in his poetry and has not been mentioned in books, interpretations and articles is creating ambiguity through rhetorical substitute. It seems that a function of substitute is avoiding repetition of words that once was considered as a defect to eloquence, but Hafez went beyond this in most cases. Through using his verbal and rhetorical knowledge, he substitutes words which have rhetorical functions along with the substitution ones. One of the most important functions of rhetorical substitute in Ghazals of Hafez is the creation of ambiguity. Through exact selection of substitute, in addition to staying immune of repetition, in many cases, he has achieved the beauty of ambiguity. In this article, first, rhetoricians’ definitions for ambiguity are presented, then rhetorical substitute is briefly defined. Next, some verses of Hafez are ambiguous due to rhetorical substitute are analyzed. Finally, 20 poems by Hafez are randomly selected and analyzed for rhetorical substitute. This is to measure the proportion of ambiguity created through rhetorical substitute to other kinds of ambiguity.