本文針對中國傳統建築之大木匠藝中，關乎規劃及設計的主要技藝「蒿尺」提出其關鍵性本質之研究分析。「篙尺」技藝為大木匠師整合性設計能力之綜合：包括房舍格局規劃、屋面曲度、尺寸設計、機件榫合關係之思考、力學合理性之判斷以及尺度比例美學觀念…等。 　　首先，本文對篙尺設計作一概略性之描述，進而針對其與尺度比例關係規劃思維的核心--「節路」，分析其思維方式及向度，以此設計項目彰顯匠人設計理念。其次，再抽取與空間格局規劃相關的設計要項「縫聲」，此照屋架空間格局圖面，進一步分析所師在設計整體房舍時，其隱藏但具支配性的空間觀念。「篙尺」技藝為中國傳統營屋技藝中的設計精髓所在，於結語中，將篙尺的設計思維本質及其隱藏觀點作綜合性的分析及歸納。

　　　　　This essay provides a research on the Chinese traditional architecture woodcraftsman's design skill, which is so-called「 Gau Scale」 design. The 「 Gau Scale」 design method include the comprehensive design abilities. The spaitial structure of house, the shape of roof, scale design, the joint relationship, the reasonability of stress and the viewpoint on aesthetics...... Friest of all, this essay gives a brief description of the Gau scale design. Then, we ivestigate the inner part of propotion planning -「Ge-Rou」, analyze the way that the designer think it over. This research item must makes a point of the design philosophy. Furthermore, we inside another item which concerns with the spatial structure of house-「 Pan-Shan」, compare with the drawing of house section, and investigate the hidden spaitial cognition of woodcraftsman during the process of design. In conclusion, we elaborate upon the essence of Gau Scale design philosophy and the comprehensive analysis of hidden spaitial cognition.