The invention discloses special joint pointing black paint for an outer wall imitation brick process and a preparation method of the black paint. The special joint pointing black paint comprises, in weight percentage, 35-40% of acrylic emulsion, 2-3% of silica solution, 2-3% of titanium dioxide, 5-10% of kaolin, 5-10% of calcium carbonate, 0.8-1% of environment-friendly solvents, 0.2-3% of film coalescing aid, 0.1-0.2% of moistening agents, 0.5-0.8% of dispersing agents, 0.3-0.5% of cellulose, 0.1-0.3% of defoaming agents, 0.1-0.3% of preservative, 0.2-3% of thickening agents, 3-5% of carbon black color paste and 28-35% of water. The special joint pointing black paint is green and environmentally friendly, alkali resistance of the black paint is normal within 144h, ageing resistance of the black paint is normal within 600h, and the black paint has grade-1 adhesive force and is high in textured-paper-resistant efficiency.