Embodiments of the present disclosure provide a method and a device for configuring an operating bandwidth and relate to the field of mobile communication technology. The method includes: obtaining bandwidth capacity parameters of user equipment (UE), wherein the bandwidth capacity parameters include a maximum operating bandwidth, a minimum operating bandwidth and a frequency band range that are supported by the UE; determining bandwidth configuration information of the UE according to the bandwidth capacity parameters, wherein the bandwidth configuration information includes a carrier identifier, an operating bandwidth and an operating frequency of each of at least one carrier, a sum of the operating bandwidths of all the carriers is not less than the minimum operating bandwidth and not more than the maximum operating bandwidth, and the operating frequency of each carrier is within the frequency band range; and sending the bandwidth configuration information to the UE, wherein the bandwidth configuration information is configured to aggregate the at least one carrier into an operating carrier by the UE. In the present disclosure, as the base station could dynamically configure the operating bandwidth for the UE according to the bandwidth capacity parameters of the UE, the bandwidth in the base station could be reasonably configured. Thus, the bandwidth utilization ratio is increased.