A method for sidelink (SL) control information (CSI) acquisition performed by a UE is provided. The method includes receiving a first SCI format from another UE, the first SCI format including resource allocation information of a second SCI format; receiving the second SCI format from the another UE based on the first SCI format, the second SCI format including a CSI request field and a source identifier (ID) field corresponding to the another UE; and generating a CSI report triggered by the second SCI format.