Abstract: A wheel structure for simulating a big-rig wheel of a big-rig semi truck is provided, and the wheel structure has a disc section which is formed with a central hole, a first annular region, and a second annular region in turn, the first annular region is provided with installation holes to install functional bolts and functional nuts of a hub plate of a transmission axle of an automobile, and the second annular region is provided with simulated bolt-and-nut elements. Furthermore, the central hole and the first annular region are covered by a decorative cap. Thus, the wheel structure can be directly installed on the hub plate of the automobile (such as a regular pick-up truck or SUV), while only one set of functional bolts and functional nuts is needed to install the wheel structure on the hub plate of the transmission axle.