The invention discloses a height-adjustable supporting frame for an escalator or a moving sidewalk, wherein a central vertical beam is supported by means of a plurality of diagonal bracing feet in sequence; the top of the central vertical beam is matched with a thread fastener by a thread plate so as to realize up-down height adjustment of the thread fastener; the top of the thread fastener can be contacted with a supported part on the escalator or the moving sidewalk in a rolling manner through a rolling ball born by a bearing piece, the friction resistance of rolling contact is less, so that the generated noise is low, and the application of force for rotating the thread fastener to adjust the height is also less. The height adjustment is convenient to operate, and the supporting frame omits a non-load-bearing cross beam referred to the background technology, so as to cause light weight, small volume and convenient carry of the supporting frame. In order to further reduce the weight of the supporting frame, the central vertical beam and the plurality of diagonal bracing feet are respectively provided with a plurality of holes.