Buddhist cosmology is prominently reflected in artistic expressions across various regions, particularly through its extensive representation in Buddhist art. From the 12th century onward, depictions of Buddhist cosmology became increasingly significant in Theravāda Buddhist nations in Southeast Asia, underscoring the enduring appeal of these cosmological concepts within local cultures. This paper examines the formation, evolution, and iconography of Buddhist cosmological paintings, with a specific focus on Traiphum representations in central Siam. By drawing on visual and textual evidence from key Theravāda Buddhist centers, including Pagan, Ayutthaya, Thonburi, and Bangkok, the study analyzes the graphic characteristics and symbolic nuances of cosmological imagery through a comparative investigation of murals, illustrated manuscripts, and related texts. Situating Traiphum paintings within the broader framework of religious art and sociopolitical structures, this research highlights their role as both doctrinal expressions and mediums of cultural and ideological integration. The findings contribute to a deeper understanding of how Buddhist cosmological theories were visually articulated, transmitted, and localized in pre-modern Southeast Asia.