The invention discloses a mine tailing brick for roads and a preparation method of the mine tailing brick. The mine tailing brick comprises tailing slag, medium sand, cement, water and additives. Thepreparation method comprises the following steps: S1, dry mixing; S2, wet mixing; and S3, pouring and molding. According to the preparation method, two times of processing molding are adopted throughdry method and wet method, so that the strength and moisture of the molded product are easy to control; the molded product is pressed in a molding cavity, so that brick preparation is more convenient,no firing is needed, no steaming is needed, energy is saved, no pollution is caused; in pressing, a vacuum mechanism is adopted for extracting air, on one hand, the downward pressure of a pressing plate can be larger, the reverse abutting force of air on the pressing plate is eliminated, and on the other hand, air holes in the brick can be eliminated, so that the strength of the brick is higher.