The invention relates to the field of ancient building repair, and particularly discloses a 
coating for ancient building repair and a preparation method thereof. The 
coating for ancient building repair is prepared from the following components: a 
pigment, 
styrene-acrylic 
emulsion, 
silicone acrylic 
emulsion, nano 
tourmaline powder, a coalescing agent, filler, a 
thickening agent, a pH 
regulator and a defoaming agent. The preparation method comprises the following steps: (1) mixing the 
pigment, the filler and the nano 
tourmaline powder, and uniformly stirring to obtain a pre-mixture; (2) uniformly mixing the pre-mixture with a part of 
silicone acrylic 
emulsion, 
grinding and dispersing to obtain a 
pigment color paste; and (3) adding the rest of the 
silicone acrylic emulsion, 
styrene-acrylic emulsion, the coalescing agent and the pH 
regulator into the pigment color paste, uniformly stirring, then adding the 
thickening agent, and uniformly stirring to obtain the 
coating for ancient building repair. The coating disclosed by the invention has the 
advantage of relatively good external environment 
corrosion resistance; in addition, the preparation method provided by the invention has the 
advantage that all the components are mixed more uniformly.