Provided are a resource allocation method and a resource allocation device, which are used for a frequency division duplexing system. The resource allocation method comprises: setting a shared frequency band; and according to resource demands for an original uplink frequency band and an original downlink frequency band in a network service, allocating the shared frequency band to the original uplink frequency band and/or the original downlink frequency band. By means of the technical solution of the present invention, a flexible duplexing solution of a FDD system can be realized, so that the allocation proportion of an uplink resource to a downlink resource is matched with the proportion of an actual uplink load to an actual downlink load, thereby achieving the purpose of rationally using resources.