Abstract: The invention relates a lockable caster wheel. The lockable caster wheel can be widely used in shopping carts, luggage carts, strollers, turnover carts, stretcher cars and many other trolleys. The controlling mechanism of the lockable caster wheel comprises a controller which comprises a signal receiving device and a locking device which is controlled by the controller. The locking mechanism further comprises a revolving damper which comprises a shell having a restricting structure and a damping wheel located inside the shell. The shell, through its restricting structure, separates from or connects with the locking device to form unlocked or locked states. The damping wheel connects with the wheel assembly. The caster wheel uses a damper. Beyond the allowed area of use, the trolleys can be slowly pushed for a few of meters because of the damper effect, but it will not suddenly stop completely. Therefore it will not present danger to the users.