The Seljuk period is one of the important periods of Islamic art in Iranian architecture, which is known for its special style and valuable buildings. The second Bayazid Mosque and Bastam Minaret are part of the magnificent architectural works of the Seljuk period in the historical city of Bastam, which are decorated with arrays of brickwork and moqrans-work. Considering that so far, little attention has been paid to these places from a technical and visual point of view, the study of these historical works becomes important. This research is organized around two basic questions: What are the technical and visual features of the arrays in the second mosque and Bastam minaret located in Bastam during the Seljuk period? And what is the most prominent decorative aspect of the architectural arrays of these buildings? The current research aims to analyze the technical features and structure of visual elements used in the arrays of the second mosque and Bastam minaret of Bastam city in the Seljuk period and also to determine the most prominent decorative aspect of the architectural arrays of these two buildings. The current research, historical-analytical method with historical approach was used and the information of this research was collected as Library and field. The findings show that in the second Bayezid Mosque and the Bastam minaret, the most important technical feature is brickwork and the different types of decorative bricks, based on their construction and usage techniques, include bricks, carved and pressed, and also the most frequent motifs are geometrical (Shamse and Chalipa) and plants respectively.