Method and apparatus for sending randomly accessed sub frame

The invention provides a method and apparatus for sending a randomly accessed sub frame. The method comprises: an uplink randomly-accessed sub frame is sent at an unauthorized carrier, wherein the uplink randomly-accessed sub frame is set by at least one of the following ways: setting CCA in a first OFDM symbol of the randomly-accessed sub frame or setting the CCA in first N continuous OFDM symbols of the sub frame and setting sending of a cyclic prefix (CP) of a random access sequence by starting with a second OFDM symbol of the sub frame and sending the random access sequence after completion of sending of the CP or setting sending of the CP by starting with a fixed sample point. The N is less than or equal to 3. Therefore, a problem that uplink random access is not perfect in the LAA system is solved and thus uplink random access in the LAA system is perfected.