A communication method and apparatus at an unlicensed band. One of the methods includes: an eNB transmits request information respectively to a small cell and UE connected to the eNB, requesting the small cell and the UE to measure a candidate channel on the unlicensed band; the eNB negotiates with the small cell for operational parameters of the small cell according to measurement results reported by the small cell and UE; and the eNB transmits the operational parameters of the small cell negotiated by the eNB with the small cell to the UE, so that the UE accesses to the small cell according to the operational parameters of the small cell and performs data transmission, transmitting data on the unlicensed band, the small cell may select a working channel having minimum interference on other neighboring systems and subjected to minimum interference from the other neighboring systems at the UE side.