The invention relates to a roughing mill water tank with wear compensation and water-leakage-proof functions and belongs to the technical field of roughing mill auxiliary devices. The roughing mill water tank comprises a water tank guide plate. An anti-wear plate is fixed to the upper surface of the water tank guide plate, and the upper surface of the anti-wear plate is paved with a sealing felt; and after the anti-wear plate and the water tank guide plate are fixed, the lower surface of the water tank guide plate coincides with the lower surface of an upper work roller guard plate. According to the roughing mill water tank with the wear compensation and water-leakage-proof functions, wear of water tank guide plate can be effectively compensated, a downward boss is avoided from appearing between the water tank guide plate and the upper work roller guard plate, therefore the accident that a plate blank butts the boss so that rolling cannot be conducted is avoided, and the on-machine life of the water tank guide plate is prolonged; and meanwhile, the phenomenon that cooled water in a roughing mill water tank body leaks onto the surface of the plate blank along the contacting surface of the water tank guide plate and the work roller guard plate is avoided, the temperature drop in the plate blank rolling process is reduced, and the rolling rhythm and the strip steel property are stabilized.