The present invention provides methods for transmitting channel status information (CSI) in a wireless access system that supports a multi-connection mode in which a terminal is connected to two or more small cells, and devices for supporting the same. A method by which a terminal reports CSI in a wireless access system that supports a multi-connection mode, according to one embodiment of the present invention, comprises the steps of: receiving a first physical downlink control channel (PDCCH) signal including first resource allocation information from a first small cell which is in a multi-connection mode state; receiving a second PDCCH signal including second resource allocation information from a second small cell which is in a multi-connection mode state; and reporting the CSI on the basis of the first resource allocation information and the second resource allocation information. At this point, the terminal maintains a plurality of connections with two or more small cells including the first small cell and the second small cell in a multi-connection mode, and the first small cell and the second small cell are arranged at different physical positions and can be connected to each other through an abnormal backhaul link.