The invention discloses a damp-proof water-proof paint for air compressors and a preparation method thereof. The paint is composed of the following raw materials in parts by weight: 36-42 parts of acrylate emulsion, 12-16 parts of tetrabutyl titanate, 6-8 parts of expanded glass beads, 5-7 parts of PAN-based carbon fibers, 2-8 parts of erucyl amide, 2-6 parts of nano copper powder colloidal solution, 1-5 parts of pigment, 4 parts of magnesium oxide nano particles, 6 parts of polyaluminium sulfate, 3 parts of dodecanol ester, 8 parts of chlorinated polyethylene and 2 parts of polyacrylamide. The paint is reasonable in component configuration, low in cost and scientific in preparation method, and the prepared paint has excellent water-proof and damp-proof performance, the corrosion resistance, the weather resistance, the storage stability, the salt fog resistance, the acid and alkali resistance, the rust resistance and the like of the paint are improved, the method is rapid in drying, good in adhesive force, convenient to construct, safe and environment-friendly. The paint is suitable for the air compressor, in particular for the air compressor in a humid environment for a long time.