The invention discloses a high-purity porous titanium-silicon-carbon ceramic preparation method. The preparation method comprises the following steps: 1) mixing titanium-silicon-carbon powder and ammonium hydrogen carbonate particles having a certain particle diameter respectively according to a mass ratio of (9:1)-(6:4) in a powder mixing machine for 6-12 hours; 2) pouring the dried mixed powder into a steel mold, and pressing to obtain a green body at a pressure of 100-1000 MPa; and 3) putting the green body in a tube furnace, introducing protective atmosphere argon, gradually raising the temperature to 1200 DEG C at a rate of 1-30 DEG C/min, keeping the temperature for 1-5 hours, and cooling in the furnace to obtain high-purity porous titanium-silicon-carbon ceramic. The preparation method provided by the invention is simple in process and low in cost, and has less limitations to preparation equipment, thereby being beneficial to industrial production.