A method of measuring and then reporting Channel State Information (CSI) in a wireless communication system supporting an unlicensed band and an apparatus supporting the same are disclosed. A method of reporting CSI by a UE includes receiving transmission burst sequence information regarding each subframe from a BS, measuring CSI using one or more resources among a Common Reference Signal (CRS), CSI Reference Signal (CSI-RS), and CSI Interference Measurement (CSI-IM) resources in one or more consecutive subframes having the same transmission burst sequence information, and reporting the measured CSI.