A method, device and system for controlling assistant information of user equipment are disclosed. The field of wireless communication technology is related, and the problem is solved that the system efficiency is reduced, for UE reports the assistant information inappropriately. The method includes: the user equipment acquiring a control parameter of assistant information configured by a network side; and the user equipment reporting the assistant information of the user equipment to the network side according to the control parameter of assistant information. The technical scheme provided in the example of the present document is applied to a LTE system or a UMTS system, which implements that the network side controls the UE reporting the assistant information.