The effects of origin and aging ways on the composition, structure and macroscopic properties of lime were studied by X-ray fluorescence analysis (XRF), X-ray diffraction analysis (XRD), thermogravimetric analysis (TG), mercury intrusion test (MIP) and field emission scanning electron microscopy (SEM). The results show that the content of Ca and Mg in lime from different origin is also different. In the process of lime aging, aging way, origin and aging time all affect the grain size and crystal morphology of calcium hydroxide, and the grain size decreases with the increase of aging time. The effect of immersion aging is better than that of sealed aging and natural aging. Lime produced by immersion aging in Nanshilou area has a smaller grain size, higher activity and higher calcium hydroxide content by immersion aging preparation. More compact microstructure can be formed after forming hardening and curing, and it has better mechanical properties. This study will guide the preparation and engineering application of lime for ancient building repair.