Mosque as the house of God has always been significant to rulers, people and Muslim artists. It is one of the most ancient architectural subjects. Varamin1Jami mosque from Ilkhanid2 era is one of the masterpieces of Iranian-Islamic architecture. It was one of the first projects which started the glorious era of renovation after the dark times of the Mongols3 invasion. Perfect stucco ornaments in mihrab4, inlaid mosaic in the iwans5 and beautifully done inscriptions with Kufic6 and Thuluth7 calligraphy in different parts of it, not only have created an admirable visual beauty but also have contributed to the spatial quality of the mosque. They deeply affect worshipers and make them concentrate and think of God only and ignore earthly
matters. This research tries to investigate the quantitative and qualitative aspects of these ornamentations and tries to find out how these ornaments affect the qualitative beauty of the space inside the mosque. The research methodology is qualitative and correlational with field study. Well decided choices on the ornaments of different parts of the mosque, the effects of Shia8, noticing some of the rules of beauty such as symmetry, repetition, massing and other areas are some of the results of this research.