The concept of "Guazhu Theory"(a theory holding that there is one or more dominating lines in a hexagram) originated with Wang Bi in his commentary on the Yijing, as well as in his work "Brief Explanations of the Principles of the Yijing." This theory aims to elucidate the comprehensive meaning of each hexagram. Subsequently, prominent scholars such as Kong Ying-da, Cheng Yi, Zhu Xi, and others in the field of Yijing studies adopted the Guazhu Theory in their respective writings to comprehend the significance of individual hexagrams. Nevertheless, there exist variations among these scholars in their interpretations and judgments regarding the principal line of each hexagram. Therefore, this paper intends to commence with an analysis of the foundational principles employed by Wang Bi in his Guazhu Theory, primarily focusing on the principles of "Esteeming the Five" and "Emphasizing the Minority." Following this, the paper will categorize the hexagrams referred to in Tang Dynasty scholar Kong Ying-da's "Right Meaning of the Yijing," examining the principles employed therein, specifically "One Hexagram, Two Masters" and "The Principal Aspect of Hexagram Significance." Finally, the paper will compare the Guazhu Theories of Wang Bi and Kong Ying-da, highlighting their differences and assessing the implications of these divergences.