The role of structure has been always considered essential in understanding the architecture. In the historical buildings of Iran, the function of structural elements follows the general form of the building. In this study, the modern structural analysis of historical building aimed at discovering the deep knowledge of experienced and skilled constructors in their works, developing the modern structural theories, and establishing modern solutions for strengthening of structural elements. Taj-Ol-Molk Dome was used as the case study that it is entitled to "the most beautiful dome". In this study, the qualitative and interpretive method was used to explore the role of aesthetics in Iranian domes. In the structural analysis based on structural simulation, the total displacement was less than 0.0002 at the maximum mode. In addition, the Von-Mises stress at the joint bearing surfaces was 2.3 × 10 6-3.5 × 10 6 which was less than the yield stress of the materials. Based on Mohr-Coulomb theory, the entire structure is below the standard risk level. A variety of brickwork styles were used based on mathematical calculations to reduce applied forces to the building. The form of Taj-Ol-Molk Dome is completely in harmony with the catenary curve form. The structural patterns lead to the bearing stress as completely compressive and without tensile and bending stress. Based on the findings, the golden ratio in the façade of building coordinated the cross section and dome-span. Finally, the structural features of the dome and the principles of structural aesthetic vision of the building are explained.