The invention discloses a preparation method of purple porcelain. The preparation method is as follows: selecting yellow clay, red porcelain clay and stones; drying, crushing, adding a blender, adding water, preparing into slurry, mud milling, forming, and drying in the shade; carrying out shape modification, carrying out primary polishing and calendaring; drawing, engraving, carrying out secondary polishing and trimming; drying in the shade at low temperature, drying at intermediate temperate; drying, carrying out primary burning and secondary burning for carburization; and discharging from a kiln, carrying out polishing treatment and preparing into a finished product. In the invention, the raw material formula, the burning technology and temperature control are improved on the basis of the traditional technology for burning black pottery; the red porcelain clay is added into the raw material only containing single yellow clay; in order to increase the density, the crushed stones areadded for supplement; and in order to increase the viscosity, proper amount of conditioner conforming to the standard is added. By utilizing the technology, in the link of the secondary burning for carburization, different kiln transmutations can be generated by controlling the temperature in the kiln, products with different colors are produced, the material for carburization is changed into lithospermum without toxicity and harm, and therefore, the produced purple porcelain has primitive simplicity, is natural, does not fade, is quietly elegant and noble and has very high value in art collection.