The invention provides a mining truck brake gap adjuster. The mining truck brake gap adjuster comprises a body, a connecting arm extending from the body, cover plates, a worm gear, a hollow worm and an adjusting shaft penetrating an inner cavity of the worm; a shaft hole is formed in the connecting arm, the cover plates are arranged on the upper and lower surfaces of the body, and the body is provided with the worm gear and the hollow worm meshed with the worm gear; rectangular teeth are arranged on the inner wall of the worm in the axis direction, an outer circle of the adjusting shaft is embedded into the rectangular teeth when penetrating the inner cavity of the worm, a protective sleeve is arranged at one end of the adjusting shaft, and a spring is arranged between the protective sleeve and the body; and a round pin is arranged on the body, and a protective sleeve groove capable of sliding along the round pin is arranged on the outer circle of the protective sleeve. The mining truck brake gap adjuster is simple in structure and ingenious in design, the truck brake gap can be effectively adjusted, and best braking is achieved.