The embodiment of the invention provides a method, a device and a system for controlling radio resources, relates to the field of communication and aims to solve the problem that radio resources are wasted in the prior art. The method comprises the following steps: when core network equipment and user equipment detects that the communication channels of the two equipment don't use the radio resources to transmit business data, the first frequency of sending a hello message to the other equipment is converted to a second frequency and sending frequency conversion information to indicate that the other party also convert the first frequency of sending a hello message to the second frequency so as to release the radio resources occupied by a first communication channel when access network equipment doesn't detect the hello message within a message detecting period. According to the embodiment of the invention, the radio resources can be controlled, and the utilization rate of the radio resources is improved.