In the manuscripts section of the Astan Quds Razavi Library, some of the most distinguished manuscripts are dedicated to Qurans, the covers of which are of different varieties and qualities, and represent great and unique developments in the art of book decoration in Iran. This type of cover has been used in the traditional binding of the Holy Quran since the middle of the ninth and tenth centuries AH, which is the peak of the development of the manuscript decoration industry, and came into existence at the end of the Timurid period. Given the importance of recognizing and deeply studying the appearance and quality of this artistic element and its importance in the manuscript creation of the Holy Quran, which is the most important book of all times in Islamic art, this research aims to answer the following question: What are the semantic layers and quality of the symbols and motifs of flowers and bushes used in the decorations of the oil covers of dated manuscripts of the Holy Quran from the Safavid to Qajar periods in the library of Astan Quds? The results show that, based on Peirce's semiotic theory, the visual arrays of the selected volumes have a composite structure in terms of the type of signs, and the presence of all three types of iconic, indexical, and symbolic signs can be identified in their collection.