Mosques are considered among the highest forms of Islamic architecture and a manifestation of beauty in the interaction of Islamic art and architecture in different eras; therefore, mosques and religious buildings were continuously recognized as pillars of the reevaluation of artistic and architectural styles and innovations following Islam. From this perspective, the Timurid architectural style can be considered as one of the prominent and brilliant periods of unique harmony between Islamic art and architecture, and the Goharshad Mosque as the result and masterpiece of the fusion and adaptation of artistic elements of architectural structures and decorations and artistic arrangements of this period, which, in addition to embodying indigenous architecture based on the temporal-spatial requirements of that era, created a spiritual and mystical space that has remained unique and unparalleled as an artistic and architectural masterpiece from the Timurid era. Therefore, the aim of the research is a comparative understanding of the interaction and harmony of architectural elements on one hand, and decorations and artistic arrangements on the other hand, in the Goharshad Mosque in Mashhad. The results of the research show that Iranian architects of this work have been able to create a valuable work with aesthetic qualities worthy of attention and with a spiritual and mystical space by creating harmony and appropriate interaction between art and architecture in the building, relying on mystical thoughts and beliefs alongside using contemporary sciences and innovative methods in construction and decorations, which best represent their era.