Abstract: A tread base includes a tread base frame unit with front and rear belt wheel sets arranged at opposing front and rear sides thereof, and an endless running belt mounted around the front and rear belt wheel sets and having slats transversely arranged on the outer perimeter thereof in a parallel manner. The running belt includes a plurality of movable sliding rollers respectively mounted at the opposing left and right ends of the slats. The tread base frame unit includes two smoothly arched sliding tracks longitudinally arranged in parallel for supporting and guiding the movable sliding rollers of the running belt to enhance the moving stability of the running belt, preventing breaking of the slats of the running belt, avoiding danger and prolonging the lifespan of the tread base.