A horizontal high-speed testing device for a spiral seal of a cone bit bearing is provided. The device comprises a shaft, a spiral sleeve and a cone. The spiral sleeve is in threaded connection to the cone. Sealing threads are provided on an inner diameter of the spiral sleeve. Both the spiral sleeve and the cone are sheathed on the shaft. By the testing device of the present invention, a spiral seal structure for a cone bit bearing is simulated, and the cone drives the spiral sleeve to rotate; the sand draining performance of the spiral seal can be tested in two ways, i.e., by measuring the time required to drain the sand-containing liquid and by measuring the weight of drained sand, so that the smooth production and application of spiral seal products can be assured.