A wireless communication apparatus, comprising a processing module and a transceiver module, wherein: the transceiver module is configured to perform data transmission; and the processing module is configured to execute processing of the following steps: performing a step of selecting a channel, wherein the step specifically comprises: selecting a channel whose bandwidth is a to-be-detected bandwidth from the WLAN system, wherein the to-be-detected bandwidth is an integer multiple of a basic bandwidth of the WLAN system, and an initial value is greater than the basic bandwidth of the WLAN system; detecting whether the selected channel whose bandwidth is the to-be-detected bandwidth is idle; and when a detection result is idle, controlling the transceiver module to use the channel to perform data transmission; or when a detection result is busy, selecting another channel whose bandwidth is the to-be-detected bandwidth from the WLAN system, and returning to the step of detecting whether the selected channel whose bandwidth is the to-be-detected bandwidth is idle; and when the following condition is met, reducing the to-be-detected bandwidth and returning to the step of selecting a channel: in the step of selecting a channel, it is detected that all selected channels whose bandwidth is the to-be-detected bandwidth in the WLAN system are busy, and the to-be-detected bandwidth is greater than the basic bandwidth of the WLAN system; characterised by the processing module is specifically configured to: select the channel whose bandwidth is the to-be-detected bandwidth from the WLAN system by using a sliding window method, wherein a width of a sliding window in the sliding window method is the to-be-detected bandwidth. the transceiver module is configured to perform data transmission; and the processing module is configured to execute processing of the following steps: performing a step of selecting a channel, wherein the step specifically comprises: selecting a channel whose bandwidth is a to-be-detected bandwidth from the WLAN system, wherein the to-be-detected bandwidth is an integer multiple of a basic bandwidth of the WLAN system, and an initial value is greater than the basic bandwidth of the WLAN system; detecting whether the selected channel whose bandwidth is the to-be-detected bandwidth is idle; and when a detection result is idle, controlling the transceiver module to use the channel to perform data transmission; or when a detection result is busy, selecting another channel whose bandwidth is the to-be-detected bandwidth from the WLAN system, and returning to the step of detecting whether the selected channel whose bandwidth is the to-be-detected bandwidth is idle; and when the following condition is met, reducing the to-be-detected bandwidth and returning to the step of selecting a channel: in the step of selecting a channel, it is detected that all selected channels whose bandwidth is the to-be-detected bandwidth in the WLAN system are busy, and the to-be-detected bandwidth is greater than the basic bandwidth of the WLAN system; characterised by the processing module is specifically configured to: select the channel whose bandwidth is the to-be-detected bandwidth from the WLAN system by using a sliding window method, wherein a width of a sliding window in the sliding window method is the to-be-detected bandwidth. performing a step of selecting a channel, wherein the step specifically comprises: selecting a channel whose bandwidth is a to-be-detected bandwidth from the WLAN system, wherein the to-be-detected bandwidth is an integer multiple of a basic bandwidth of the WLAN system, and an initial value is greater than the basic bandwidth of the WLAN system; detecting whether the selected channel whose bandwidth is the to-be-detected bandwidth is idle; and when a detection result is idle, controlling the transceiver module to use the channel to perform data transmission; or when a detection result is busy, selecting another channel whose bandwidth is the to-be-detected bandwidth from the WLAN system, and returning to the step of detecting whether the selected channel whose bandwidth is the to-be-detected bandwidth is idle; and when the following condition is met, reducing the to-be-detected bandwidth and returning to the step of selecting a channel: in the step of selecting a channel, it is detected that all selected channels whose bandwidth is the to-be-detected bandwidth in the WLAN system are busy, and the to-be-detected bandwidth is greater than the basic bandwidth of the WLAN system; characterised by the processing module is specifically configured to: select the channel whose bandwidth is the to-be-detected bandwidth from the WLAN system by using a sliding window method, wherein a width of a sliding window in the sliding window method is the to-be-detected bandwidth.