Islam is an integral way of life which considers beauty to be a divine quality. In fact, Islam is the religion of beauty and perfection. Islamic architecture refers to any architecture in Islamic culture or in Islamic context. Islamic architecture exhibits the sacred order of Islam and its distinctive feature is religious aspect. Yet, Islamic architecture is not completely varied from all other architectural styles; even, it borrows from some of them such as Persian architecture. The aim of this study is investigating the importance of beauty and aesthetics in Islamic architecture. Results show that Islam does not consider art and beauty as a luxury. It considers beauty to be a divine quality. Unity is one of main aesthetically concepts which has merged in Islamic architecture; It was called as a base for life cycle and was reflected on art and architecture to such an extent that we can count it as the language of Islamic architecture. Based on this language, Paradise is a perfect epitome in all respects of aesthetics.