This paper aims to investigate the geometric proportions, scales, and numerological connotations embedded within the plans of the capitals of Yuan dynasty: Shangdu, Dadu, and Zhongdu. Building upon previous research, this paper proposes that all three capitals exhibit distinct geometric proportions in their layout plans, primarily manifested in the shape and proportional relationships between the outer city, imperial city, and palace city within each capital. Additionally, it observes integer multiple relationships between the area of outer city and palace city (sometimes including the imperial city) in each capital. Furthermore, in Dadu and Zhongdu, the area of palace cities and rectangular plots occupied by their main halls also display integer multiples. Drawing upon ancient architectural terminologies found in texts such as Zhouli Kaogongji, which describes measurement systems, and Yingzao Fashi, which provides architectural principles, the paper generalized these principles to “inside a capital, everything is measured according to the size of a palace”, “inside a palace everything is measured according to the size of the main hall”, or “all principles of constructing capitals are based on the palace.” Moreover, the numberical values involved in the aforementioned ratios and scales of the three- loop city layout and the main palace (including blocks, streets, etc.) in each capital, when converted into measurement units such as chi, bu, zhang, li, and mu used during Yuan dynasty, carry significant Chinese traditional numerological connotations. These numbers symbolize the ideologies of Yijing (Book of Changes), ancient Chinese astronomy, and the legal calendar, aligning with the knowledge structure and ideological system attributed to Liu Bingzhong, the main planner of Shangdu and Dadu, who was reputed for his extensive knowledge in areas such as Yijing and Shao’s Jingshi Shu, astronomy, geography, the legal calendar, and the Three Methods and Six Ren. This paper sheds light on the profound connections between the geometric proportions, numerical values, and ideological influences found within the layout plans of Yuan’s capitals, providing references of the complex intellectual framework and ideological systems of Liu Bingzhong, the principal planner of Shangdu and Dadu.