A frequency domain resource activation method, wherein the method comprises: receiving, by an access network device, first information sent by a terminal, wherein the first information comprises first assistance information of a frequency domain resource unit of the terminal, wherein the frequency domain resource unit is a bandwidth part, BWP, wherein the first assistance information comprises or indicates working status information of the terminal; and activating, by the access network device, a frequency domain resource unit based on the first information; characterized in that the working status information of the terminal comprises the following piece of information: temperature information of the terminal, wherein the received first information carries the temperature information of the terminal and the temperature information of the terminal is an overheating level, and wherein the method further comprises determining, by the access network device, based on the overheating level and a table of correspondence between an overheating level, a maximum bandwidth that is of a BWP and that is preferred by the terminal and a maximum quantity that is of BWPs and that is preferred by the terminal, a maximum bandwidth that is of a BWP and that is preferred by the terminal and a maximum quantity that is of BWPs and that is preferred by the terminal, and selecting, by the access network device, a to-be-activated BWP based on the determined maximum bandwidth of a BWP and the determined maximum quantity of BWPs. receiving, by an access network device, first information sent by a terminal, wherein the first information comprises first assistance information of a frequency domain resource unit of the terminal, wherein the frequency domain resource unit is a bandwidth part, BWP, wherein the first assistance information comprises or indicates working status information of the terminal; and activating, by the access network device, a frequency domain resource unit based on the first information; characterized in that the working status information of the terminal comprises the following piece of information: temperature information of the terminal, wherein the received first information carries the temperature information of the terminal and the temperature information of the terminal is an overheating level, and wherein the method further comprises determining, by the access network device, based on the overheating level and a table of correspondence between an overheating level, a maximum bandwidth that is of a BWP and that is preferred by the terminal and a maximum quantity that is of BWPs and that is preferred by the terminal, a maximum bandwidth that is of a BWP and that is preferred by the terminal and a maximum quantity that is of BWPs and that is preferred by the terminal, and selecting, by the access network device, a to-be-activated BWP based on the determined maximum bandwidth of a BWP and the determined maximum quantity of BWPs. temperature information of the terminal, wherein the received first information carries the temperature information of the terminal and the temperature information of the terminal is an overheating level, and wherein the method further comprises determining, by the access network device, based on the overheating level and a table of correspondence between an overheating level, a maximum bandwidth that is of a BWP and that is preferred by the terminal and a maximum quantity that is of BWPs and that is preferred by the terminal, a maximum bandwidth that is of a BWP and that is preferred by the terminal and a maximum quantity that is of BWPs and that is preferred by the terminal, and selecting, by the access network device, a to-be-activated BWP based on the determined maximum bandwidth of a BWP and the determined maximum quantity of BWPs.