A method for detecting an idle channel, applied in a wireless communication system, wherein the method for detecting the idle channel comprises: performing channel measurement for channels which are needed for transmitting data by means of beamforming, wherein said performing channel measurement includes: performing a wireless signal sense and measuring a received wireless signal strength on each of the channels, wherein the wireless signal strength is an average value of signal strength in a preset period of time; and determining a channel is in an idle state, wherein said determining the channel is in the idle state includes at least one of: when beamforming data is transmitted at a fixed power, determining that the channel is in the idle state under a condition that signal strength detected in an opposite direction of a transmission direction of data to be transmitted is less than or equal to a threshold A1 and signal strength detected in a same direction of the transmission direction of the data to be transmitted is less than or equal to a threshold A2; or when beamforming data is transmitted at a variable power, calculating a transmission power of beamforming data satisfying a set modulation coding rate, and determining that the channel is in the idle state under a condition that the transmission power is supported by a current transmitting station, signal strength detected in an opposite direction of a transmission direction of data to be transmitted is less than or equal to a threshold A1 and signal strength detected in a same direction of the transmission direction of the data to be transmitted is less than or equal to a threshold A2. performing a wireless signal sense and measuring a received wireless signal strength on each of the channels, wherein the wireless signal strength is an average value of signal strength in a preset period of time; and determining a channel is in an idle state, wherein said determining the channel is in the idle state includes at least one of: when beamforming data is transmitted at a fixed power, determining that the channel is in the idle state under a condition that signal strength detected in an opposite direction of a transmission direction of data to be transmitted is less than or equal to a threshold A1 and signal strength detected in a same direction of the transmission direction of the data to be transmitted is less than or equal to a threshold A2; or when beamforming data is transmitted at a variable power, calculating a transmission power of beamforming data satisfying a set modulation coding rate, and determining that the channel is in the idle state under a condition that the transmission power is supported by a current transmitting station, signal strength detected in an opposite direction of a transmission direction of data to be transmitted is less than or equal to a threshold A1 and signal strength detected in a same direction of the transmission direction of the data to be transmitted is less than or equal to a threshold A2. when beamforming data is transmitted at a fixed power, determining that the channel is in the idle state under a condition that signal strength detected in an opposite direction of a transmission direction of data to be transmitted is less than or equal to a threshold A1 and signal strength detected in a same direction of the transmission direction of the data to be transmitted is less than or equal to a threshold A2; or when beamforming data is transmitted at a variable power, calculating a transmission power of beamforming data satisfying a set modulation coding rate, and determining that the channel is in the idle state under a condition that the transmission power is supported by a current transmitting station, signal strength detected in an opposite direction of a transmission direction of data to be transmitted is less than or equal to a threshold A1 and signal strength detected in a same direction of the transmission direction of the data to be transmitted is less than or equal to a threshold A2.