The work aims to systematically deconstruct the underlying mechanisms of aesthetic transformation in women's attire in the Tang and Song Dynasties from the perspective of Hippolyte Taine's "spiritual climate" theory. According to the research findings, in terms of natural drivers, the climatic cooling during the "Third Little Ice Age" from the Northern Song onward promotes a shift from Tang-era sheer, revealing garments to multi-layered thermal structures in the Song Dynasty, giving rise to cold-resistant forms such as beizi (a long-sleeved outer garment), elongated sleeves, and head veils, alongside significantly increasing the use of woolen textiles. With regards to institutional drivers, the rise of the commoner class, strengthened civil bureaucracy, and Neo-Confucian ethical discipline in the Song Dynasty construct a female dress ethics centered on "docility and frugality" through hierarchical regulations (Yu Fu Zhi: Treatise on Carriages and Dress) and familial moral constraints, forming an ideological countercurrent to Tang's nomadic-inspired fashion. As for cultural drivers, the literati-aesthetic paradigm of "slenderness and subtle elegance" replaces Tang's "opulent voluptuousness," manifested in beizi's elongated silhouettes, muted color palettes, and motifs of plum, orchid, bamboo, and chrysanthemum, achieving the aesthetic compensation under ethical suppression via "floral-adorned naturalism." The interplay of these three drivers ultimately catalyzes a paradigm shift in Chinese sartorial history, from "open diversity" to "restrained rationality", reflecting women's societal reconfiguration from "self-expression" to "ethical vessel."