Abstract: Building upon existing research on the modular system of Chinese timber architecture during ancient times, particularly focusing on the caifen system (length unit of carpentry system in measurement), this paper introduces a new approach centered on the zucai (full unit bracket) modular unit. Utilizing data extracted from the detailed surveying and mapping report of the Main Hall of Zhenguo Temple, this paper presents an interpretation of the scale rule based on the zucai modulus unit, offering a competitive alternative to existing data fitting methods with similar error levels. The paper addresses the common occurrence of the 47 fen phenomenon in previous research, proposing hypotheses regarding arch length, discussing the arrangement of yinggong (shadow bow-shaped bracket) and the length of eave-rafter, and elucidating the distinct characteristics of the two types of lengths in the bow-shaped bracket. A comprehensive analysis of component scale, spatial span, structural relationships, and facade aesthetics is conducted. Additionally, revisions to early research findings on the scale rule of the Main Hall of Foguang Temple are presented in the appendix.