A wheel clamp includes a clamp body, a movable rod pivotally connected to the clamp body, a connecting rod fitted on the movable rod, and a rotating unit disposed in a lock core seat of the clamp body. The connecting rod has a threaded section for connecting with a screw. The rotating unit has a rotating rod to be inserted into an accommodating trough of the screw. A first engaging member is secured to the accommodating trough of the screw. A second engaging member is secured to the rotating rod of the rotating unit. The second engaging member has a second engaging block to mesh with and drive a first engaging block of the first engaging member so the connecting rod is able to be moved relative to the screw.