Natural hydraulic lime (NHL) has both pneumatic and hydraulic components, so NHL can be widely used in the restoration of historic building masonry walls. Industrial solid waste contains certain elements of Ca and Si, meeting the mineral element requirements for the preparation of NHL. In this study, limestone, slag, fly ash and silica fume were used as raw materials to prepare NHL by calcination with different calcium-silicon ratio parameters. The composition, product composition, microstructure, mechanical properties, and setting time of NHL were tested using XRD, TG, compressive and flexural tests, SEM-EDS, and Vicat apparatus. Meanwhile carry out engineering applications. The study shows that it is feasible to prepare NHL by industrial solid waste calcination. The prepared NHL is mainly composed of calcium hydroxide and dicalcium silicate. The 28 d hydration carbonization products include hydrated calcium silicate, CaCO₃, and Ca(OH)₂. NHL can be prepared by calcium-silicon ratio at 4.6 that meets European standards. The repair results of the weathered surface of masonry meet the requirements of reversibility and compatibility. The article responds to the call of national policies for the protection of historical architectural relics and ecological environment, which is conducive to protecting historical culture and creating better economic benefit and environmental benefit.