The invention discloses a PVC color hard board and a preparation method thereof. The PVC color hard board is prepared from the following raw materials in parts by weight: 120-140 parts of PVC resin, 4-10 parts of stabilizer, 0.6-1.2 parts of internal lubricant, 0.5-1.1 parts of modifier, 31-39 parts of filler, and 0.8-1.4 parts of external lubricant. The preparation method comprises packing, mixing and forming. The PVC color hard board prepared by the method has the characteristics of excellent chemical stability and corrosion resistance, great hardness, high strengthening degree, ageing resistance, no water absorption, no deformation, uniform mixing, easy processing and high production efficiency; the filler prepared by sieving, calcining and grinding is added in the processing materials of the board, and can achieve an effect of improving the strength and hardness of the board; the filler is obtained by processing ardealite, thus achieving an effect of improving the quality of the board, and solving the environmental pollution problem caused by stacking a great amount of the ardealite.