A method for listening on an uplink channel by a terminal device, comprising: performing first listen before talk, LBT, and sending a first data packet on a first uplink burst after the first LBT succeeds; determining a second contention window size, CWS, wherein on condition that a first time length is greater than a first time threshold and first indication information indicating a HARQ status is not received after the first uplink burst, the second CWS is greater than a first CWS; and/or on condition that the first time length is less than or equal to the first time threshold and the first indication information indicating the HARQ status is not received after the first uplink burst, the second CWS is equal to the first CWS; and performing second LBT based on the second CWS; wherein the first time length is an interval between a first reference time unit and a second reference time unit corresponding to the first uplink burst, the first CWS is used for a LBT previous to the second LBT, and the first reference time unit is later than the second reference time unit corresponding to the first uplink burst; wherein the method further comprises: sending a second data packet on a second uplink burst on condition that the second LBT succeeds, wherein the second uplink burst is later than the first uplink burst; wherein the first reference time unit is a time unit for determining the second CWS, or the first reference time unit is a starting time unit of the second uplink burst; and the second reference time unit corresponding to the first uplink burst is a time unit in the first uplink burst. performing first listen before talk, LBT, and sending a first data packet on a first uplink burst after the first LBT succeeds; determining a second contention window size, CWS, wherein on condition that a first time length is greater than a first time threshold and first indication information indicating a HARQ status is not received after the first uplink burst, the second CWS is greater than a first CWS; and/or on condition that the first time length is less than or equal to the first time threshold and the first indication information indicating the HARQ status is not received after the first uplink burst, the second CWS is equal to the first CWS; and performing second LBT based on the second CWS; wherein the first time length is an interval between a first reference time unit and a second reference time unit corresponding to the first uplink burst, the first CWS is used for a LBT previous to the second LBT, and the first reference time unit is later than the second reference time unit corresponding to the first uplink burst; wherein the method further comprises: sending a second data packet on a second uplink burst on condition that the second LBT succeeds, wherein the second uplink burst is later than the first uplink burst; wherein the first reference time unit is a time unit for determining the second CWS, or the first reference time unit is a starting time unit of the second uplink burst; and the second reference time unit corresponding to the first uplink burst is a time unit in the first uplink burst. sending a second data packet on a second uplink burst on condition that the second LBT succeeds, wherein the second uplink burst is later than the first uplink burst; wherein the first reference time unit is a time unit for determining the second CWS, or the first reference time unit is a starting time unit of the second uplink burst; and the second reference time unit corresponding to the first uplink burst is a time unit in the first uplink burst.