The invention discloses a synthetic method of a conductivity-adjustable-and-controllable alkali-activated red-mud-based semiconductor cementing material. According to the synthetic method of the conductivity-adjustable-and-controllable alkali-activated red-mud-based semiconductor cementing material, industrial waste red mud, silica fume, black carbon and a sodium silicate aqueous solution are put into an agitating device to carry out mixing; the conductivity-adjustable-and-controllable alkali-activated red-mud-based semiconductor cementing material is obtained through mold forming and maintenance, wherein the mass ratio of the red mud to the silica fume is 9: 1, the adulterate amounts of the black carbon, sodium metasilicate nonahydrate and water are 1.5 percent to 4.5 percent, 15 percent and 28 percent to 42 percent of the sum of the masses of the red mud and the silica fume respectively. The stable conductivity of the prepared alkali-activated red-mud-based semiconductor cementing material is regulated and controlled between 0.14(S/m) to 1.20(S/m) during a 28d maintenance period; when a maintenance period is shorter than the 28d maintenance period, the conductivity of the conductivity-adjustable-and-controllable alkali-activated red-mud-based semiconductor cementing material changes along with the prolonging of the maintenance period; after the 28d maintenance period, the conductivity of the conductivity-adjustable-and-controllable alkali-activated red-mud-based semiconductor cementing material does not change along with the prolonging of the maintenance period. The method is novel and simple; no three wastes are discharged in a whole technical process; the completely harmless utilization of the mud red can be realized.