This study evaluates the conservation challenges of the Main Hall of the Yu Temple in the Great Yu Mausoleum in Shaoxing, Zhejiang. As an exemplary early 20th-century concrete structure mimicking traditional timber construction, the hall’s historical significance lies in its innovative integration of traditional Chinese architectural form with modern reinforced concrete. It represents the era’s engineering innovations essential for replicating the structural and aesthetic qualities of timber using concrete. The State Council’s designation of the site as a national key cultural relics protection unit in 1996 underscores its historical and scientific importance. Following an in-depth analysis of the architectural history and structural features of the hall, this study provides a comprehensive assessment of its pre-restoration condition, identifying three critical conservation issues. The paper then details the repair techniques and strategies employed. The restoration process involved non-destructive testing to evaluate the concrete’s condition, the use of advanced materials such as carbon fiber and polymer-based mortars for reinforcement and restoration without compromising the historical appearance, and the application of hydrophobic treatments and protective coatings to enhance durability and extend the lifespan of the original murals. The study underscores the necessity of preserving the hall’s historical integrity while ensuring its long-term stability and safety. It highlights the ethical considerations of honoring the original design intent and the cultural significance of the timber-imitated concrete construction. This research demonstrates the efficacy of a holistic approach that integrates historical research, scientific analysis, and technological innovation in the preservation of 20th-century architectural heritage for future generations.